Nigeria's President Goodluck Jonathan has cut short a trip to Equatorial Guinea following Wednesday's bomb attack in the capital, Abuja, his spokesman has said.
Security has been tightened in the city following the blast which killed 21 people and wounded 52 others.
Mr Jonathan's decision to return follows strong criticism that he is not doing enough to curb violence.
Militant Islamist group Boko Haram has stepped up attacks in Nigeria.
In April, it killed more than 70 people in a bomb blast at a bus stop on the outskirts of Abuja.
The group also said it was behind a car bomb attack near a bus station in the city's Nyanya suburb in May, which killed at least 19 people and injured 60 others.
It has not commented on the latest explosion, which ripped though a busy shopping district.
Police say a suspect has been arrested, but have not released details about him.
Presidential spokesman Reuben Abati said Mr Jonathan received news of the blast as he was arriving at his hotel in Equatorial Guinea's capital, Malabo, for an African Union (AU) summit, Nigeria's privately owned Premium Times newspaper reports.
He decided to fly back to Abuja to deal with the crisis, Mr Abati said.
The BBC's Mansur Liman in the capital says the security forces have cordoned off the area around the blast.
Police have ordered an increase in security and surveillance operations in and around Abuja to prevent further attacks, he says.
Mr Jonathan's decision to return appears to be an attempt to address a growing public perception that he is not concerned about the plight of victims, our correspondent adds.
BBC
