Two explosions blasted a crowded marketplace and killed dozens of people on Saturday night in Nigeria's northeastern Maiduguri city, the birthplace of the armed group Boko Haram.
At least 51 were confirmed dead, according to the International Red Cross.
Bloodied people screaming for help could be seen running out of buildings billowing with smoke, witnesses said. Trader Mallam Samalia said some people were blown apart.
The second blast caught people trying to help those injured in the first explosion in the Bintu-Suga neighborhood of the Ngomari suburb, he said.
The explosion appeared to come from a pickup truck, Samalia told The Associated Press by telephone.
"I'm seeing people carrying bloody bodies," he said. "There are parts of bodies littering the street."
Mechanic Yahaya Adamu said he was on his way home when he heard the blasts, two minutes apart.
"There's black smoke everywhere now," he said. "I'm running home to see if my family is safe."
It was the first attack in months in Maiduguri, capital of Borno state and the headquarters of a military force tasked with suppressing the 4-year-old Boko Haram uprising that has killed thousands.
More than 300 people were killed in February alone in attacks, which have increased in frequency and deadliness, all in the neighboring states of Yobe and Adamawa.
There is growing anger at the Nigerian military's apparent inability to halt the attacks, with soldiers reportedly abandoning checkpoints in two recent attacks that killed nearly 100 people, including 59 students, because they were outnumbered and outgunned.
That anger was fueled by reports that a military fighter jet targeting Boko Haram hideouts bombed a village in Yobe state and killed at least 20 civilians on Friday, according to survivors.
Borno, Yobe and Adamawa state cover one-sixth of Nigeria and have been under a state of emergency since May.
Al Jazeera and wire services