A bomb blast has rocked the Emab Plaza shopping complex in the Wuse district of the Nigerian capital, Abuja.
According to local reports scores of shoppers were killed in the attack.
"I can see human parts and some bodies scattered on the ground but we are too scared to get closer for fear of another bomb," a reporter at the scene said.
"Many traders and visitors to the mall are still trapped in the burning building," Nigeria's Vanguard reported.
Nigerian emergency services are at the scene to assist those wounded in the attack.
Witnesses said that people could be seen running from the complex with blood on their clothes.
Video footage has emerged of firefighters attempting to extinguish a convoy of cars destroyed in the bomb blast.
Manzo Ezekiel, National Emergency Management Agency spokesman, told AFP news agency: "You can see smoke billowing from the sky. It's a very crowded place."
No group has yet claimed responsibility for the attack but Boko Haram has previously committed attacks in Abuja as it continues to wage a violent insurgency against President Jonathan Goodluck's regime.
Last month, a car bomb attack killed at least 19 people and injured more than 60 at a bus station in the Nigerian capital.
The group, who wish to create an Islamic caliphate within Nigeria, kidnapped more than 200 schoolgirls in April in the village of Chibok, bringing global attention to the west African nation's fight against terrorism.
Three northern states - Borno, Yobe and Adamawa - have been placed under a state of emergency since May last year.