A suicide car bomber killed five people on a street of popular bars and restaurants in the northern Nigerian city of Kano on Sunday evening, in an area mostly inhabited by southern Christians, police said.
Kano police spokesman Musa Majiya said the bomber struck Gold Coast Street in the Sabon Gari or "foreign quarter" of the North's biggest city.
"I heard a loud blast. And there was a lot of smoke. Soldiers came in to cordon off the place and ambulances were rushing people to hospital," witness Abdul Dafar, who lives a block away from the blast, said, adding that he had seen four dead bodies in the aftermath.
There was no immediate claim of responsibility, but blame is likely to fall on violent Islamist group Boko Haram, whose struggle against the Nigerian state has killed thousands over the last five years.
The militants also operate in neighbouring Niger, Cameroon and Chad, and President Goodluck Jonathan described them as West Africa's al-Qaeda on Saturday in Paris, where regional leaders met France's President Francois Hollande to discuss how to tackle the growing threat posed by the group.
Liquor stores targeted
The Islamists grabbed world headlines with abduction of more than 200 school girls a month ago from a remote village in the northeast. Britain, the United States and France have pledged to help rescue them.
Boko Haram has frequently attacked Sabon Gari, whose liquor stores are also a cause of friction with Kano's Islamic police. The area has for decades housed ethnic Igbo traders from the South, who are predominantly Christian.
Nigeria's population of 170 million is split roughly evenly between Christians and Muslims.
Multiple bomb blasts in Sabon Gari killed at least 15 people in July and an attack on a bus station there in March 2013 killed 25.
The focus of Boko Haram's insurgency is on the northeast border area with Cameroon, where it has repeatedly attacked military outposts and massacred villagers with growing ferocity.
Outrage over kidnapping
But two bombs on the outskirts of the capital Abuja last month that killed 105 people between them showed the Islamists can strike across north and central Nigeria. Boko Haram is now seen as the main security threat to Africa's biggest economy and top oil producer, although it has so far spared the commercial hub of Lagos and the oil fields in the South.
Outrage over Boko Haram's kidnapping of the school girls has prompted Nigerian President Goodluck Jonathan, criticised at home for his government's slow response to the crisis, to accept U.S., British and French help in the hunt for the girls.
U.S. officials have said the effort to retrieve the kidnapped girls is now a top priority. But it has been complicated by Nigeria's early reluctance to accept assistance and U.S. rules banning aid to forces that commit human rights abuses.