ALEXANDRIA, Egypt (Reuters) - In Egypt's second city, medical student Ahmed Nabil lives in fear that the police may come and arrest him any day. As a member of the Muslim Brotherhood, he is part of a movement facing an onslaught by the security forces which toppled Islamist President Mohamed Mursi in July.
"These days we can be picked up at any time," said Nabil, whose parents are also members of the organization, Egypt's oldest Islamist movement and a supporter of Mursi.
The Brotherhood's discipline and hierarchy helped it win elections after the 2011 popular uprising that ousted autocrat Hosni Mubarak, eventually propelling Mursi into power. But now the army-led government and its supporters regard the Brotherhood as a terrorist group and enemy of the state. The security forces and police, feared and despised under Mubarak, are lauded for cracking down on the organization.
The Brotherhood denounces violence and says it is committed to peaceful protest. But as members go into hiding, its key building blocks - local groups of seven members known as usras - are under pressure.
"The most important person for me is the head of my usra," said Nabil. "I get everything from him."
In Nabil's eyes, the usras, which provide everything from Koran studies to marriage counseling, are crumbling. That raises the risk the organization will fracture, and that some members will abandon peaceful activism to take up arms.
In a sign of how the Brotherhood is retreating, Nabil has bought a new, unregistered mobile phone. He encrypts text messages and is careful about what he writes on Facebook, fearful that the authorities are monitoring communications.
Nabil said he has lost five friends killed in demonstrations and that he narrowly escaped arrest when he took part in a protest. He worries about survival and avoiding jail. The clampdown, he said, could radicalize some members.
This month suspected militants killed six Egyptian soldiers near the Suez Canal, fired rocket propelled grenades at a state satellite station in Cairo and exploded a car bomb near an Egyptian army intelligence building in the city of Ismailia. More than 50 people have been killed and more than 270 wounded in recent clashes between the police and protesters supporting the Muslim Brotherhood.
Even as questions remain over who mounts such attacks, it seems clear the recruitment pool for radicals has grown significantly since Mursi's overthrow.
"Not all people in the opposition can go on resisting peacefully if this unbelievable pressure continues, especially the detentions of leaders who pushed the movement to remain peaceful," said Nabil. Before they were imprisoned, top Brotherhood leaders often told followers that avoiding violence would give the movement the moral high ground against the government.
"All these military actions against us, including killing and torture and arrests, push us to respond with force. One prays that God ends the crisis before we reach the situation in Syria," he said, referring to civil war in that country. "As our grand guide (top leader) said, 'Our peaceful ways are stronger than a bullet.'"
The government makes no distinction between the Brotherhood and al Qaeda-inspired militants based in the Sinai Peninsula who have sharply stepped up attacks against soldiers and police since Mursi was overthrown. The authorities say the Brotherhood's members are terrorists out to spread an Islamic caliphate across several nations, not focus on Egypt's well-being.
A top security official who has monitored the Brotherhood for decades told Reuters: "The usra has been destroyed in a very big way. The Brotherhood member is taught not to think on his own, just to take orders. This is how the group functions. So if there is no one to give them orders it means the group is in trouble."
The usra was devised by Hassan al-Banna, founder of the Muslim Brotherhood, to indoctrinate and mobilize followers. Usras typically used to meet once a week for at least three hours, usually at the home of a member. The usra leader could be so pivotal that members sought their permission to travel to Cairo.
During past crackdowns, the usra survived by adapting. Its size was reduced to three members when restrictions were tightened. Those small units avoided arrest by speaking while walking down streets or meeting in tea houses, not homes. In prison, the usra became the number of men in each cell.
After Mursi fell, the Brotherhood had hoped to mobilize millions of protesters; but the army reacted forcefully, bulldozing a protest camp at Rabaa al-Adawiya in eastern Cairo on August 14, killing hundreds of Mursi's supporters. Security forces have arrested many top Brotherhood leaders, including Mursi, on charges of inciting or perpetrating violence.
Before the leaders were detained, they sent messages to Brotherhood officials urging them to ensure that usras continued, according to the head of an usra and other Brotherhood members. But members are struggling.
In Alexandria, Abu Bakr al-Masri is the head of an usra and worships in a spartan Brotherhood mosque on the bottom floor of an apartment building. For decades, the Brotherhood has used such mosques in rundown neighborhoods across Egypt to deepen its influence and raise funds.
Masri's usra has not met since Mursi fell. He is proud of his position but worried because he can no longer guide young men.
"I gave people advice on everything. Even if you have trouble with your wife you come to me," he said, sitting in his apartment, a block from the mosque. "The usra is under a lot of pressure now. I speak to people in the usra by phone, but it is always brief and we never have a chance to speak about the important issues."
There are usras for women and Masri's wife, Um Abdullah, heads one. It, too, has not met since July and she is a member of another that has stopped gathering.
"I am sitting here doing nothing," she said, complaining about the Brotherhood's isolation. Um Abdullah, who was veiled, is tasked with spreading the Brotherhood's views of how Muslim families should approach life. There is little scope for that now. "I used to be able to go out in the streets and tell other women about our vision, about the true Muslim family," she said. "Now I can only wander in our building and speak to my neighbors."
The Brotherhood has few options. Many Egyptians turned sharply against the organization during Mursi's year as president. He was accused of trying to give himself sweeping powers, entrenching the Brotherhood in the institutions of state and mismanaging the economy. The Brotherhood denies those charges.
While limited protests by Mursi supporters continue, General Abdel Fattah al-Sisi, head of the military, has announced a political roadmap promising new elections. The transition includes rewriting the constitution that was drafted by an Islamist-dominated assembly, passed in a referendum and signed into law by Mursi. The most contentious feature of the new constitution may be a clause banning religious political parties.
The Brotherhood wants nothing to do with the transition and its supporters are retreating. In one tight-knit Brotherhood community in Alexandria, four families have already fled for fear of arrest after the security forces and army began conducting overnight searches of apartment buildings, according to local Brotherhood supporters.
In the office of Ahmed Fahim, a lawyer in Alexandria who represents Muslim Brotherhood members, stands a photograph of a past leader of the Palestinian militant group Hamas, an offshoot of the Brotherhood. It's a small sign of Fahim's defiance.
His day usually starts with a brief walk to the courthouse, which he believes treats the Brotherhood unfairly. "Why do they let common criminals see their day in court while Muslim Brotherhood detainees are seen as a security risk and are only allowed hearings in jail?" he said.
A Justice Ministry official said security forces advise the ministry that taking Brotherhood members to a courthouse poses a security risk because there could be protests and other problems.
For Fahim, all around are reminders of the Brotherhood's steep fall from power. In the street a young boy sells posters showing army chief Sisi with Gulf Arab leaders who pumped billions of dollars into Egypt after Mursi fell. At the courthouse, overlooking the sea, a blue police truck displays a poster showing Sisi beside Gamal Abdel Nasser, a former president of Egypt who ordered a crackdown on the Brotherhood after an attempt to assassinate him.
Fahim seemed resigned to the idea that the Brotherhood will experience hardship. "We knew from the beginning that our path would not be lined with roses, but thorns," he said. He no longer thinks it is realistic to demand Mursi's reinstatement.
He worries about the fate of the usra - but also the possibility that members of the Muslim Brotherhood may turn to armed struggle. "People won't be able to hold back," he said, though he calls for restraint.
At his modest apartment, Fahim spoke proudly about how his son Muiz, 10, and daughter Amena, 7, joined him at the demonstration at Rabaa al-Adawiya, which at times swelled to tens of thousands of protesters. The family laughed when the daughter said she didn't like Sisi or Mubarak. But the mood soured when they recalled how the Rabaa protest was crushed.
The conversation turned to how unpopular the Brotherhood is. A joke doing the rounds illustrated the grim mood: A boy who wants to have his father killed leaves their fifth floor apartment, goes to the ground floor and posts a sign at the entrance, "Muslim Brotherhood headquarters is located on the fifth floor, apartment three."
Like Fahim, some outside experts fear the severity of the crackdown could backfire. "The weekly usra meeting is a very important tool in shaping the mindset and behavior of Brotherhood members. The alternative might be an extreme path," said Khalil al-Anani, senior fellow at The Middle East Institute in Washington.
"This might replicate the 1950s and 1960s when the state cut links between the leadership and grassroots, leading in the end to the deviation of youth and creation of groups that started insurgencies."
While Reuters found no evidence of Brotherhood members joining extremist groups, the authorities are now portraying most Islamists as one broad group of terrorists.
When reporters first met Nabil, the medical student in Alexandria, he was upbeat about the prospect of the Brotherhood returning to power. He had spent a great deal of time reading commentaries from Brotherhood officials about how many military coups had ultimately failed.
He was especially interested in reading about Algeria. There the army's decision to cancel elections in 1991, which Islamists had won, plunged the North African country into a civil war that killed at least 150,000 people.
But later Nabil grew downbeat. With the top Muslim Brotherhood leaders behind bars and his usra leader on the run, Nabil has no one to help him get through tough times. Fear of arrest has forced Islamists to cut down on protests. Maintaining secrecy is important: Protest locations are only shared with a few. False destinations are sometimes announced on Facebook to confuse the authorities.
If Nabil does run into his ursa leader at a protest, there is little time to talk, he said. Demonstrations are often cut short to avoid clashes with security forces, who may have been tipped off by informers.
Pro-government activists called baltagiya, or thugs, usually attack the processions from behind, using everything from rocks to swords and guns, demonstrators say. Nabil pointed to Egyptian flags held by Brotherhood members and said: "Actually those flags have another purpose. When we are attacked, people holding them flip them around and use the wooden poles to defend protesters."
He cannot count, as the Brotherhood once did, on popular support. During one demonstration, Nabil and a friend looked up at the balconies of surrounding buildings to find people insulting them and hurling water. "Every week we count the numbers of people who are against us," he said.
There is no doubt the army-backed government has the upper hand, and Brotherhood members often compare the current campaign against the group to the repression imposed by Nasser in the 1950s and 1960s.
In Alexandria, Abdel Latif Mohammed, a Brotherhood member who is now too old to kneel for prayers in the mosque, recalled how jailers during Nasser's crackdown whipped his feet and then set dogs on him. He recalled, too, that 15,000 people were arrested in one night. Yet in Mohammed's eyes, the current situation is worse.
No government spokesman would comment on the scale of the crackdown. But a senior security official told Reuters: "This group has to be stopped. They are terrorists with an international agenda. They don't care about Egypt."
Even lawyers who defend Muslim Brotherhood members say they no longer feel safe and move from one house to another to avoid arrest. In August, in an interview with Reuters, Khalaf Bayoumi, a leading Muslim Brotherhood lawyer in Alexandria, predicted he would be arrested. He is now being held with other Islamists at the sprawling Borg al-Arab prison on the edge of Alexandria.
Visitors to the prison say groups of 35 Mursi supporters are crowded into cells built for 10. Army tanks guard the premises.
Before he was incarcerated, Bayoumi said that to survive, the Brotherhood must preserve the usra. "If the Brotherhood loses that, the group will fall," he said.
Additional reporting by Abdel Rahman Youssef in Alexandria; Editing By Richard Woods and Simon Robinson