Nigeria's military on Friday attacked Boko Haram Islamist strongholds across the northeast, launching air strikes on insurgent camp with dozens of militants killed in the fighting, the military said.

Several thousand soldiers have spread across three northeastern states where President Goodluck Jonathan imposed a state of emergency, saying Boko Haram had seized territory and declared war on the government.

More than 2,000 Nigerian troops have begun an offensive to retake territory seized by Islamist insurgents in the remote northeast, some of them raiding camps in a game reserve, a military source told Agence France Presse Thursday.

The military has launched a sweeping operation to flush out fighters from Boko Haram, a radical group which says it wants to create an Islamic state in northern Nigeria.

Nigeria's military on Wednesday announced the "massive"deployment of troops to its restive northeast, after the president declared a state of emergency in areas where Islamist insurgents have seized territory.

A separate military source speaking on condition of anonymity told Agence France Presse that fighter jets would also be deployed to the region, raising the possibility that Nigeria could carry out air strikes within its own territory.

Five foreigners who were kidnapped last month when heavily armed pirates stormed their cargo ship off Nigeria's oil-producing southern coast have been released, the vessel's German operator said Tuesday.

The Gulf of Guinea, which includes the waters of Benin, Nigeria and Togo is an emerging piracy hub, with gunmen frequently targeting oil ships both to steal crude and seize foreign hostages in order to get ransom payments.

A Nigerian court on Monday sentenced an alleged member of the Iranian Revolutionary Guard and his Nigerian accomplice to five years in jail each over an illegal arms shipment.

Azim Aghajani and Nigerian Ali Abbas Jega were detained in 2010 when authorities at a Lagos port discovered 13 containers of weapons that had been declared as construction materials.

The purported head of Nigerian Islamist group Boko Haram has claimed two recent deadly attacks in the northeast in a video obtained by Agence France Presse Monday, which also depicts women and children apparently being held hostage.

The video features Abubakar Shekau, declared a global terrorist by the United States, seated on a rug with a kalashnikov resting behind his right shoulder.

Nigeria's leading opposition parties agreed Saturday to merge into an electoral behemoth they vowed would defeat President Goodluck Jonathan in 2015 polls.

Two parties -- the Congress for Progressive Change (CPC) and the All Nigeria People's Party (ANPP) -- approved the move in separate conventions aired live on television.

Nigerian police have found 17 pregnant teenage girls in a raid on a house, and were searching Friday for a woman suspected of planning to sell their babies, a spokeswoman said.

Joy Elomoko of the southeastern Imo state police said all the girls were between 14 and 17 years old and that 11 small children were also found in the house.

Suicide bombers targeted troops in two towns in war-torn northern Mali on Friday, leaving four of the attackers dead and two Malian soldiers wounded, military sources said.

The first attack was against soldiers from neighboring Niger stationed in Menaka, a Saharan desert commune 300 kilometers (185 miles) east of Gao, with only the bomber being killed, Nigerien and Malian military sources on the ground told Agence France Presse.

Gunmen from a shadowy cult ambushed a group of police officers in central Nigeria, killing 23 of them and then setting fire to their bodies, the state's police chief said Thursday.

"A detachment of 60 police... came under attack from members of Ombatse cult in an ambush," Nassarawa state police chief Abayomi Akeremale said of the attack on Tuesday.