* Between 50-100 students taken by Boko Haram raiders
* "We thought they were soldiers," says girl who escaped
* Nigerians complain of feeling insecure in their nation
* President Jonathan is under pressure before Feb. elections (Adds government statement, more girls escaped)
By Lanre Ola and Isaac Abrak
MAIDUGURI/ABUJA, April 16 (Reuters) - Islamist rebels duped dozens of Nigerian schoolgirls into thinking they were soldiers come to evacuate them before abducting between 50 and 100 in their latest anti-government raid, officials said on Wednesday.
Gunmen suspected to be members of the radical Islamist movement Boko Haram swooped on Chibok town in Borno state and on its nearby all-girls government secondary school late on Monday, calling on the students to leave their beds in the hostel.
The mass abduction of schoolgirls aged between 15 and 18 has shocked Nigeria and showed how the five-year-old Boko Haram insurgency has brought lawlessness to swathes of the arid, poor northeast, killing hundreds of people in recent months.
It occurred the same day a bomb blast, also blamed on Boko Haram, killed 75 people on the edge of the capital Abuja, stirring fears of violence spreading from the north of Africa's No. 1 oil producer and most populous nation.
Nigeria's government pledged to step up its fight against "terrorism", which it said had "nothing to do with religion, ethnic group or tribe".
The Chibok students, who had returned to sit final-year certificate exams at their school despite a Borno state-wide closure of educational centres because of recent Boko Haram attacks in the northeast, initially obeyed the armed visitors, thinking they were Nigerian troops there to protect them.
"When we saw these gunmen, we thought they were soldiers, they told all of us to come and walk to the gates, we followed their instructions," 18-year-old Godiya Isaiah, who later managed to escape the abductors, told Reuters.
But when the armed men started ransacking the school stores and set fire to the building, the terrified girls being herded at gunpoint into vehicles realised they were being kidnapped.
"We were crying," Isaiah said, recounting how she later jumped from a truck and ran away to hide in the bush. Other girls were packed into a bus and some pick-ups.
There was still confusion over exactly how many girls had been kidnapped. Initial accounts from Chibok said around 100, but Borno state governor Kashim Shettima said reports from parents and guardians of children missing so far totaled 50 students, although this might not be the final figure.
Shettima said at least 14 girls had managed to escape and reach safety. Borno state education commissioner Inuwa Kubo said other girls told the same story as Isaiah.
"They went into the bus unsuspecting," he told Reuters.
"They were lured into the vehicle because they were told that the school was going to be attacked," he added. The attackers also raided nearby Chibok town, ransacking stores and offices there and killing several people, witnesses said.
Boko Haram, which in the Hausa language broadly means "Western education is sinful", has previously attacked several schools as symbols of secular authority, killing pupils and teachers, as well as Christian churches and Nigerian state targets such as police, army and government offices.
Nigerian police and army patrols were on Wednesday still scouring the bush and hills around Chibok for the missing girls.
Chibok is not far from a rugged area of forest, hills and caves where military officials say Boko Haram has camps near the border with neighbouring Cameroon. They have abducted girls in the past to be sex slaves for the fighters and to do camp work.
No one has claimed responsibility for the abduction or for the rush hour bomb blast on Abuja's outskirts, which put the capital on alert around three weeks before the central city was due to host a high-profile World Economic Forum on Africa.
But President Goodluck Jonathan has pointed the finger of suspicion for the bombing at Boko Haram, bringing home to Nigerians in the centrally-located capital that the Islamist insurrection ravaging poorer states hundreds of kilometers (miles) to the northeast could also strike much closer to home.
On Tuesday afternoon, a bomb scare at the National Assembly, caused lawmakers and bureaucrats to hurriedly abandon their offices. Banks also closed before officials gave the all-clear.
With elections due in February, Jonathan is under intense pressure to contain the Boko Haram insurgency and additional communal sectarian violence in Nigeria's centre-north which badly tarnish the West African state's newly acquired status as the largest economy on the continent.
Ordinary citizens, and delegates to a conference discussing national unity in a country split between a mostly Muslim north and largely Christian south, all called on the government to do more to end violence and improve security across the territory.
"We are left in the hands of God," said Emeka Obi, who works at a business centre in the capital.
Some delegates to the conference called for closure of Nigeria's borders with its Sahel neighbours Niger and Chad and also with Cameroon, reflecting fears that Boko Haram had bases there and also ties with al Qaeda-linked Saharan jihadists.
There are also suspicions some local politicians may be manipulating the violence to try to serve their own interests.
"We must advise politicians to take politics out of this entirely. There are external sponsors to this cannibalism we are witnessing," said Kunle Olajide, a delegate to the conference.
Nigerian authorities plan to deploy over 6,000 police and soldiers to protect participants in the May 7-9 "African Davos" World Economic Forum which draws regional heads of state and business leaders in a mirror of the Davos, Switzerland event. (Additional reporting by Chijioke Ohuocha in Lagos and Felix Onuah in Abuja; Writing by Pascal Fletcher; Editing by Tom Heneghan)