Officials say a bomber on motorbike rammed into a police convoy in Jalingo, the capital of Taraba state. Another 20 people were injured in the blast, but the police official was not harmed.
No one has claimed responsibility for the blast, which occurred near the state ministry of finance and police headquarters.
The attack comes a day after gunmen in northern Nigeria killed at least 15 people in an assault on a university theater used for church services.
Security officials said the gunmen threw small explosives into the site at Bayero University in Kano, then fired on worshippers as they ran outside.
One of the more than 20 people wounded in Sunday's attack said the assault happened just before the service began.
"We were about to start the mass, then we start hearing gunshots, pah pah pah, and I ducked down because I am a retired soldier, and I said I will not run away to anywhere," he said.
A faculty member, Nasir Fagge, told VOA Hausa Service that security had been increased at the school in the days before the attack in light of other deadly incidents in Kano.
No one has claimed responsibility for the attack, which resembled others carried out by the Islamic militant group Boko Haram.
The group claimed responsibility for deadly attacks on Thursday at the offices of This Day newspaper in the northern city of Kaduna and the capital, Abuja.
Boko Haram, whose name means "Western education is a sin" in the Hausa language, is trying to turn Nigeria into an Islamic state. Human Rights Watch says the group has killed more than 1,000 people since 2009.
Nigerian President Goodluck Jonathan has come under increasing domestic and international pressure to bring an end to the violence.
Nigeria, Africa's most populous nation, is split between the majority-Muslim north and the predominantly Christian south.
