A suspected suicide attacker slammed a car bomb into a church during services on Sunday in the Nigerian city of Kaduna, killing two other people and sparking reprisal attacks by Christians.

Christian youths took to the streets with machetes and sticks afterward, targeting people they believed to be Muslims as anger again boiled over due to the repeated church bombings in recent months, an AFP correspondent reported.

A wave of attacks by suspected Boko Haram Islamists in northeastern Nigeria has killed at least 23 people and destroyed several buildings, a hospital official and residents said Saturday.

A nurse at the Potiskum general hospital spoke of 20 bodies being brought to the morgue, while residents said three bodies were buried by their families following explosions and shootings in the restive city on Thursday.

A series of attacks by suspected Boko Haram Islamists in northeast Nigeria has killed a number of people and destroyed several buildings, residents and authorities said Friday.

Explosions and gunfire that started late Thursday shook the city of Potiskum, with residents reporting several schools and a government building burnt, along with a number of dead.

Kidnappers have boarded a ship off Nigeria and abducted seven crew members, including six Russians and one Estonian, in the latest such incident in the region, French company Bourbon said on Wednesday.

"Bourbon confirms that seven crew members, six Russians and one Estonian, were kidnapped during the boarding of the Bourbon Liberty 249, which occurred on October 15, 2012 in Nigeria," a statement from the oil industry servicing firm said.

Armed robbers opened fire on a group of people as they left prayers at a mosque in the northern Nigerian state of Kaduna on Sunday, killing about 20, a military spokesman said.

A resident reported that the gunmen were disguised in police uniforms as they stormed the mosque in the village of Dogon Dawa just before sunrise, shooting both those still worshiping within the building as well as some outside.

Police in northern Nigeria said Wednesday they have arrested eight suspected Islamist militants over the killing of two police officers who were shot while guarding medical personnel.

The officers were killed by motorcycle-riding gunmen on Tuesday while escorting a group going door-to-door around the city of Kano conducting polio vaccinations, police spokesman Magaji Majia said.

Gunmen have shot dead a Chinese national who was working as a chef for a construction company in Nigeria's troubled northeast, a company official said Monday.

Borno state, where the attack occurred on Sunday, has been hit hard by the radical Islamist group Boko Haram but the shooting in the town of Gubio may have been motivated by robbery.

A blast in Nigeria's eastern city of Jalingo injured a woman and seven others, including three children, the national emergency agency said on Saturday, correcting an earlier statement that she had died.

The agency said the woman had in fact been unconscious following the blast but had since come round.

Nigerian soldiers moved house to house on Wednesday in an urgent bid to hunt down attackers responsible for the massacre of 26 people who were shot or had their throats slit in a student housing area.

The attack in the early hours of Tuesday near a polytechnic university shook the town of Mubi, located in Nigeria's volatile northeast.

Gunmen massacred at least 26 people in a student housing area of northeast Nigeria on Tuesday, calling victims out by name before shooting them or slitting their throats, officials said.

The attack occurred in the early hours in the town of Mubi, where the military last week carried out a high-profile raid against Islamist extremist group Boko Haram, which has been waging a deadly insurgency.