AMMAN (Reuters) - Residents of the city of Deraa, cradle of the pro-democracy protests that have swept Syria, painted a chilling picture on Monday of an assault by security forces using tanks, heavy artillery and machine guns.
Artillery pounded the town, electricity and most telephone lines were cut and soldiers took over mosques and other key locations, residents reported.
Foreign correspondents are being kept out of Syria so the reports could not be verified, but residents contacted by telephone painted a consistent picture of a ruthless attempt to subjugate the city through military force.
A prominent activist said at least 18 people were killed by gunfire and tank shelling, adding to the grim toll of a month-old uprising against President Bashar al-Assad which human rights groups say has already cost 350 lives.
"Army units are pounding Deraa at this moment. There seems to be no end to the sounds of heavy machinegun fire and occasional mortars," said resident Abu Salem, several hours after the tanks rolled in at dawn.
Another witness said he had seen bodies lying in a street near the Omari mosque after eight tanks and two armored vehicles were deployed in the old quarter. A pall of black smoke hung over the city.
Most residents sought refuge indoors, but a few groups of defiant youths played cat-and-mouse with the troops patrolling on foot, shouting "down, down with Bashar."
It was a dangerous game.
"Anywhere they find people coming out in the streets, they attack with heavy ammunition," said another resident.
Clouds of black smoke from the gunfire filled the sky above the city, said Abu Salem, from the large al-Masalmah tribe.
Deraa, which in its heyday was a stopping place on the Hijaz Railway built during Ottoman rule a century ago, was more recently known as a recruiting ground for cadres of the ruling Baath Party and agents of the secret police.
In the past six weeks, the Sunni Muslim city has emerged as a center of defiance against the autocratic rule of Assad and his minority Alawite family.
Hours before troops stormed the city center and the old quarter, nearly 2,000 people gathered in the old Omari mosque, focal point of almost daily protests.
One community leader after another criticized what they termed the "inhumanity and criminality" of the security forces during recent crackdowns, and called for the peaceful popular uprising against Assad to spread, residents said.
Abu Salem said the echo of gunfire drowned out the dawn call to prayer after the tanks and soldiers arrived.
"They occupied several mosques, including the Omari mosque and Sheikh Abdul Aziz (mosque), to ensure that even volunteers or imams cannot use minarets to ask for blood or urge medics to help the wounded," he added.
He said dozens of tanks and scores of armored personnel carriers took up positions in the old quarter and the main squares in Mahatta, the heart of the commercial area.
"They stationed tanks even in public gardens and security patrols seem to have orders to shoot on the spot."
Witnesses described how black-clad snipers took up positions on high government buildings.
"It's terrifying and shows the authorities will not spare anyone to subdue people and end our resistance and yearning for freedom," said one witness.
Asked whether the residents were fighting back -- Deraa is a region where tribal traditions of vengeance are strong -- Abu Salem said that, until Monday, most residents had resisted calls to avenge the dozens of deaths.
"Defenseless people cannot just watch as they get slaughtered. There is hardly a family that does not have a martyr now," he said.
Editing by Kevin Liffey and Andrew Dobbie