Suspected Nigerian Islamists opened fire and set off bombs at a market in the northeastern city of Maiduguri on Monday, killing at least 30 people, a medic and a witness said.
Gunmen believed to be members of the Islamist sect Boko Haram stormed the fish section of Baga market and sprayed stallholders and vendors with bullets, traders said, reporting that women and children were among the dead.
"The number of dead could not be less than 30," a Maiduguri hospital nurse told AFP.
The military confirmed the assault on the market but denied any civilian deaths, saying security forces had killed eight assailants and safely detonated bombs planted by the attackers.
"At about 1:30 (1230 GMT) this afternoon at Baga market of Maiduguri metropolis some gunmen suspected to be members of Boko Haram attacked and shot civilians at the market," Lieutenant Colonel Hassan Mohammed, spokesman of a special military unit in the city, told AFP.
He said several people had been wounded but that there was "no civilian death at this time".
The military "immediately came to the rescue of the situation and safely detonated three bombs planted by members of the sect and shot and killed eight members of the sect," Mohammed said.
However, one trader who have his name as Mairami, said six gunmen stormed the food and commodities market and "opened fire indiscriminately. At least 30 people including women and children were killed."
Another vendor by the name Gana gave a similar account of the attack in the city, the stronghold of Boko Haram which has been blamed for a deadly wave of bombings and shootings mainly in the north of Africa's most populous country.
Witnesses said the gunmen set off eight home-made bombs inside the market, destroying stalls. The entire market was deserted after the attack.
"The gunmen just opened fire killing people. I saw three military vans piled with bodies leaving the market. There were several explosions after the shooting," Gana said.
The attackers accused traders of collaborating with the military following the arrest last week of a suspected Boko Haram member in the market, witnesses said.
Mairami said one gunman shouted angrily that traders had "teamed up with soldiers" to help arrest members of the sect.
"'We have henceforth waged war against you'," Mairami said the gunman had declared, before spraying bullets on both vendors and customers.
The nurse said it was difficult to get a precise death toll from the attack as security forces did not take the bodies to the morgue but allowed relatives to claim their loved ones for immediate burial, according to Muslim rites.
Last week, traders overpowered a gunmen suspected to be a Boko Haram member and handed him over to the military.
Maiduguri, the capital of Borno state and the home base of Boko Haram, has seen some of the worst violence blamed on the extremist sect, which has focused its attacks on the mainly Muslim north.
The insurgency blamed on Boko Haram has killed more than 200 people already this year, including at least 185 in coordinated gun and bomb attacks in Nigeria's second city of Kano on January 20, its deadliest ever strike.
The shadowy sect has said it wants to create a Islamic state across Nigeria's deeply-impoverished mainly Muslim north and some analysts believe the Islamists are tied to like-minded extremist groups such as Al-Qaeda.
Other analysts insist the sect is pursuing a narrowly domestic agenda.