Boko Haram fighters on Sunday stormed the northeast Nigeria city of Maiduguri, sparking an hours-long battle with troops for control of the strategically crucial Borno state capital, witnesses said.
Four residents told AFP by telephone that the Islamist assault began at roughly 3:00 am (0200 GMT) and that fierce fighting was ongoing at the southern edge of the city between the insurgents and troops backed by vigilantes.
"The whole city is in fear," said resident Adam Krenuwa. "People are afraid of what will happen if Boko Haram defeats the security forces."
Boko Haram's last attempt to take over Maiduguri just seven days ago was repelled by the military.
But, in that January 25 assault, the militants captured the town of Monguno just 125 kilometres (80 miles) outside the city and seized control of a military base.
Most experts said last week that the insurgents would likely launch another attempt on Maiduguri before Nigeria's February 14 general election.
Resident Fannami Dalwaye said the fighting at roughly 9:00 am was concentrated in Mulai, roughly three kilometres south of the city, and more vigilantes were seen deploying to the area as reinforcements.
"People are fleeing into the city," Dalwaye said.