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By Isaac Abrak
ABUJA, May 1 (Reuters) - A blast on the outskirts of Nigeria's capital Abuja killed several people on Thursday, witnesses said.
The explosion hit the suburb of Nyanya, close to the site of a morning rush hour bomb attack at a bus station on April 14 that killed at least 75 people.
"There was a loud blast then a ball of fire," witness Lateef Adebayo told Reuters by telephone. "There were many dead bodies and ambulances were rushing there."
It was not immediately clear what had caused the blast.
Islamist group Boko Haram, which is waging an insurgency against the Nigerian government to carve out an Islamist enclave in Africa's No. 1 oil producer, claimed responsibility for the April 14 blast in Nyanya, and threatened further attacks.
A Reuters photographer in a nearby hospital counted 11 charred bodies that medical staff said had been brought there from the site of the explosion.
Another witness, Joe Udofia, said there was a "deafening explosion, then the area near Nyanya bridge was on fire. There were many people in the vicinity."
The blast came a week before Abuja was due to host the World Economic Forum on Africa, an annual gathering which brings together international leaders, policy makers, entrepreneurs and philanphropists.
Nigeria's government had announced a big security operation to protect the capital during the forum. (Reporting by Isaac Abrak and Tim Cocks; Writing by Tim Cocks; Editing by Andrew Heavens and Pascal Fletcher) )