Nigeria has repatriated around 11,000 foreigners mainly from Niger and Chad over the past six months to curb a growing Islamist insurgency, the immigration services said on Monday.

"The latest number of foreigners repatriated as at this morning is 11,000," immigration services spokesman Joachim Olumba told Agence France Presse, updating an earlier figure.

Nigeria's Islamist sect Boko Haram said it was behind a suicide bomb attack Sunday that killed at least three outside a church in the central city of Jos, and warned of more such assaults.

Witnesses said a car packed with explosives rammed the gate of a perimeter fence and exploded a few meters (yards) from the wall of an 800-seat church hall in the volatile city.

A suicide bomber drove an explosives packed car into a church in Nigeria's volatile central city of Jos on Sunday and killed three people, church leaders told Agence France Presse.

The attack is the latest in a country grappling with what have become almost daily assaults, most of them blamed on the Islamist sect Boko Haram.

Suspected Islamists razed a police station and killed 14 people, whose bodies were found burned, in an overnight raid in Nigeria's northeastern city of Gombe, witnesses said Saturday.

The attackers also tried to break into a prison elsewhere in Gombe in an apparent bid to free the inmates, but were unsuccessful, witnesses further said.

Nigeria's military chief said Thursday the Islamist Boko Haram sect, blamed for attacks that have claimed hundreds of lives, has ties to al-Qaida, the first time a top security official has publicly drawn such links.

"We have been able to link the activities of the Boko Haram sect to the support and training the sect received from AQIM (Al-Qaida in the Islamic Maghreb)," Air Chief Marshal Oluseyi Petinrin said.

Explosions and gunfire rocked a suburb in northern Nigeria's largest city of Kano early Wednesday where Islamists staged deadly attacks in January, an Agence France Presse reporter and residents said.

An AFP correspondent heard at least six huge explosions followed by gunshots, just before Muslim dawn prayers, which continued for around an hour.

A 52-year-old Lebanese identified as Habib Youssef Hashem was found stabbed to death in his hotel room in the Nigerian capital Lagos, the National News Agency said Saturday.

The parents of Hashem, who hails from the town of Hasbaya, urged the foreign ministry to cooperate with the Lebanese embassy in Lagos to investigate his murder and help them take the necessary measures to repatriate his body.

Pirates fired on a cargo ship around 110 nautical miles off the coast of Nigeria on Monday killing the captain and chief engineer, the International Maritime Bureau said.

"Armed pirates chased and fired upon a drifting bulk carrier. Vessel raised alarm and headed towards Lagos. All crew except the bridge team took shelter in the citadel," the IMB Piracy Reporting Centre said in a statement.

Nigeria on Saturday deployed thousands of police for a governor's election in Bayelsa, the oil-rich home state of President Goodluck Jonathan that has been wracked by pre-vote violence.

"We have fortified every area of the state to ensure a hitch-free election. Some 10,000 police personnel and 5,000 other security agents have been deployed," Bayelsa state police spokesman Equavoen Emokpae told AFP.

A lead poisoning epidemic in Nigeria's north that has killed 400 children and affected thousands is the worst in modern history, but cleanup has not even begun in many areas, Human Rights Watch said Tuesday.

"Thousands of children in northern Nigeria need immediate medical treatment and dozens of villages remain contaminated two years into the worst lead poisoning epidemic in modern history," the US-based group said in a statement.