Clashes between the Nigerian army and Boko Haram militants have claimed the lives of at least two Nigerian security forces and five gunmen, an official report says.

The army issued a statement saying Nigerian forces raided two buildings suspected of being Boko Haram safe houses in the Hotoro Dan Marke and Brigade region of Boko city on Saturday.

The incident of violence linked to militants marks the first event in months in the largest northern city of Nigeria.

The report said security forces further uncovered a terrorist plot to carry out “simultaneous” attacks in Abuja and Kano.

The Boko Haram militant group claimed responsibility for the August 2011 bombing of the UN headquarters in Abuja. Two dozen people died in the attack.

The group has claimed responsibility for a number of deadly gun and bomb attacks in various parts of Nigeria since 2009.

In May, the Nigerian government declared a state of emergency in three states in the northeast and launched a campaign against Boko Haram in the area.

Over the past four years, violence in the north of Africa’s most populous country has claimed the lives of 3,600 people, including killings by the security forces.

According to the Brussels-based International Crisis Group, ethnic and religious conflicts in Nigeria claimed the lives of over 14,000 people between 1999 and 2009.