Police in northeastern Nigeria say a bomb targeting a police vehicle exploded in the city of Maiduguri as a governor's motorcade approached from the airport.

The blast happened Monday after the governor of Borno state, Kasim Shettima, arrived from the capital, Abuja, where he won a legal challenge to his election.

No one claimed responsibility for the bombing, but members of the radical Islamist sect Boko Haram are suspected of throwing the device at a police vehicle.

The state police commissioner said there were no injuries from the explosion.

Boko Haram said it was behind a series of attacks earlier this month in northern Nigeria that killed more than 100 people.

It also claimed responsibility for an August 26 attack on the U.N. headquarters in Abuja that killed more than 20 people.

Boko Haram militants say they are fighting to establish a strict Islamic state in the north. The group does not recognize the oil-rich country's government or its constitution.