Residents of a troubled northern Nigeria city accused soldiers of indiscriminately firing and killing several people Monday, after a bomb exploded on an army patrol.

Troops were deployed to the area following an early morning explosion that hit a military patrol van and injured at least two soldiers in the city of Maiduguri, a military statement said.

According to witnesses, the soldiers used whips and the butts of their guns to beat people but the level of violence later escalated, including setting fire to homes and shops.

"Initially, soldiers that came after the explosion harassed residents, whipping them," said one Maiduguri resident, who requested anonymity.

"But later they went on a shooting spree and started setting homes and shops on fire," he said, putting the number of dead at about 30.

Another resident, who did not give an estimate of the death toll, said that "soldiers came into the neighbourhood and started attacking people, shooting everybody in sight."

"They went about burning houses and businesses," he added, also speaking anonymously.

The violence in the Lagos Street-Gwange area of the northeastern city forced the closure of the Gamboru market, with traders shuttering their stalls amid the unrest, according to witnesses.

The military spokesman of Borno state, of which Maiduguri is the capital, said the explosion went off when a military patrol van drove over the device.

"There was a bomb blast involving a JTF vehicle at about 7:15 am (0615 GMT) today along Lagos Street in Maiduguri metropolis. Two soldiers sustained injury," said Lieutenant Colonel Sagir Musa in a statement, referring to a military Joint Task Force.

Two residents claimed they saw six dead soldiers being evacuated from the military van.

Rights groups have previously accused the military of using brutal tactics when responding to attacks on their personnel.

Asked about the latest allegations, Musa said, "I don't have any comment."

Maiduguri is considered the home base of Islamist group Boko Haram, blamed for killing more than 1,400 people in northern and central Nigeria since 2010.

No group has claimed Monday's attack on the military vehicle, but it resembled those previously carried out by the insurgents, who have said they want to create an Islamic state in the north of Africa's most populous country.

Boko Haram Islamists have killed scores of security personnel in bomb and shooting attacks since 2010.

Nigerian officials have been seeking to show success in the fight against the extremists with a number of raids and arrests.

The military on Sunday claimed the killing of 30 alleged Boko Haram members, including someone described as a senior field commander, following a gun battle that lasted several hours in the nearby city of Damaturu.

Nigeria has said it was engaging in a back-channel talks with the Islamists in an effort to stem the violence, but previous attempts at dialogue have failed and senior Boko Haram leaders have ruled out negotiations.