Gun battles between security forces and suspected Islamists in Nigeria's Damaturu have killed at least 34 people, including three police officers and a soldier, a hospital source said Tuesday.

"So far we have 34 dead bodies in the morgue," said the senior hospital official after the fighting broke out Monday and continued Tuesday in the northeastern city now under round-the-clock curfew. "The figure is likely to rise.

Boko Haram Islamists on Monday claimed suicide attacks on three churches in northern Nigeria's Kaduna state that killed at least 16 and sparked riots that killed dozens more.

"Allah has given us victory in the attacks we launched against churches in (the cities of) Kaduna and Zaria which resulted in the deaths of many Christians and security personnel," said the email statement sent by Abul Qaqa, the purported Boko Haram spokesman who has similarly claimed previous attacks.

Suicide attacks on three churches and reprisal violence that saw Christians target Muslims in northern Nigeria have killed at least 45 people and the toll could rise further, a rescue official said Monday.

"As at last night, around 10 pm, the death toll stood at 45," the rescue official said on condition of anonymity as he was not authorized to issue death tolls. "The death toll is expected to rise when we get updated."

Bomb blasts damaged five churches in four cities in Nigeria's northern Kaduna state on Sunday, injuring dozens of worshippers and leading to an immediate curfew, officials said.

The number of casualties in the blasts in the neighboring cities of Zaria and Kaduna and in the southern Christian-dominated Nassarawa and Barnawa was not immediately clear. Police and the military cordoned off the areas.

A suicide bomber drove his car at a church in central Nigeria while gunmen opened fire on another church in the northeast Sunday, killing at least three and wounding dozens, officials said.

The assaults were the latest in a series targeting churches in Africa's most populous nation and largest oil producer, with many of the previous attacks claimed by Islamist group Boko Haram.

Gunmen in Nigeria's troubled north killed two policemen and a customs officer, while two civilians wounded in the separate attacks died later, witnesses said Saturday.

In the region's largest city Kano, two gunmen on Saturday shot dead an official of the secret police, Aminu Isa, and fled, a resident told Agence France Presse.

A suicide blast at the police headquarters in Nigeria's restive city of Maiduguri Friday killed at least two policemen and wounded six other people, authorities and witnesses said.

It was the latest violence to hit the tense northeastern city that has been at the center of Islamist group Boko Haram's insurgency, which has killed more than 1,000 people since mid-2009.

A bomb killed one person early Friday in the northern city of Maiduguri where Islamist sect Boko Haram has carried out series of deadly attacks, the army and residents said.

The improvised explosive device (IED), concealed in a bag kept under a public shed, exploded around 6:00 am (0500 GMT) in the Gidan Dambe district of the volatile city, they said.

The Islamist group Boko Haram has claimed responsibility for the killing of a former Nigerian deputy police chief in the northern city of Kano and vowed more of such attacks.

"Yesterday God gave us victory and we succeeded in killing a former DIG (deputy inspector general)... in Kano city," the sect said in an email statement to reporters late Wednesday.

Nigerian soldiers have killed at least 16 militants, the army said Wednesday, after gunfire and blasts rocked an area of the country's northeast where Islamists were believed to be hiding.

"It's confirmed," Colonel Victor Ebhaleme told Agence France Presse when asked about reports of 16 Boko Haram members being killed in the city of Maiduguri. "They came to attack part of the city," he said, declining to provide details.