A truck has exploded in a huge fireball killing at least 56 people in the northeast Nigerian city of Maiduguri, the leader of a civilian group that recovered the bodies said, the latest attack in a city repeatedly hit by Boko Haram fighters.
Tuesday's bomb rocked Maiduguri's largest roundabout near the crowded Market where elderly women line the road selling peanuts and kola nuts as snacks to morning commuters.
Sadiq Abba Tijjani, leader of the Civilian Joint Task Force, told the Associated Press news agency his group recovered at least 56 dead bodies from the blast site.
He said that they managed to identify 21 of the dead but the rest "were either burnt or damaged beyond recognition".
Other witnesses also estimated the death toll to around 50. However, some government officials said only 17 people died in the explosion. Officials regularly play down the death toll.
The defence ministry said in a tweet that an "improvised explosive device" went off in "a van loaded with charcoal" and that the area had been cordoned off.
One witness said the bomb went off just after the market opened at 8am before most traders or customers had arrived.
Unruly crowds tried to attack firefighters deployed to the scene, accusing them of arriving too slowly and hindering their efforts to put out the raging blaze, the AFP news agency reported.
While there was no immediate claim of responsibility, blame was likely to fall on armed group Boko Haram, which was founded in Maiduguri more than a decade ago and has killed thousands during a five-year uprising.
Attacks in the city were once a daily occurence but a huge military offensive launched last year and backed by vigilante fighters had some success in flushing the armed men out of the city into the remote corners of Borno state, of which Maiduguri is the capital.
Boko Haram is suspected of detonating several bombs in the past week in Nigeria. They include the bombing of a shopping centre in Abuja, which killed 24 people; a bomb at a medical college in northern Kano city, which killed at least eight; and an attack on a hotel brothel in northeast Bauchi city that killed 10.
The group has attracted international condemnation since its April abduction of more than 200 schoolgirls from a northeastern town, many of whom remain captive.