A powerful bomb blast targeting soldiers followed by gunfire rocked the troubled Nigerian city of Maiduguri on Tuesday, with at least 10 people killed, an official and a hospital source said.

Residents claimed soldiers reacted to the bombing by shooting indiscriminately and burning homes, with troops having been accused of such abuses following previous attacks after alleging residents were complicit.

An explosion damaged a mosque early Saturday in a town in Nigeria's southern oil rich Niger Delta, police and a government source said.

"There was an incident in Sapele... several persons were injured, but no deaths," a government official who asked not to be named told Agence France Presse.

A powerful explosion rocked the northern Nigerian city of Kaduna on Wednesday, killing at least eight people, wounding many others and causing panic, but the cause of the blast remained unclear.

Witnesses and officials described a grisly scene at the blast site, with a number of shops and houses destroyed and body parts littering the area which rescue workers rushed to retrieve.

Suspected Islamists on Sunday bombed two police buildings, two banks and killed three people, including a policeman and a soldier in the volatile northern Nigeria's Bauchi State, residents said.

The attacks by suspected members of the radical Boko Haram sect, which also seriously injured two other policemen, happened in the town of Azare and lasted four hours, they said.

A Nigerian rights group on Saturday reported fresh spills from a pipeline operated by Agip, the local subsidiary of Italian oil group Eni, in a community in the southern oil state of Bayelsa.

The Environmental Rights Action (ERA)/Friends of the Earth Nigeria (FoEN), said in a statement it visited Kalaba community on Friday and observed five spill points on the pipeline which was spewing oil into the environment.

The death toll in clashes between Muslim and Christian ethnic groups in central Nigeria has risen to 25, a local official said Saturday, following a mass burial that included four of his own children.

Pam Choji, a counselor in Barkin Ladi local government council, who lost four children in Wednesday's attack, said that 23 of the victims were entered on Friday.

Clashes between Muslim and Christian ethnic groups in central Nigeria on Thursday caused "enormous" destruction, with a number of people dead and houses burned, a military officer said.

Captain Charles Ekeocha said the army had imposed a 24-hour curfew on the Barkin Ladi area of Plateau state after the clashes, the latest in a series of violent incidents between the two communities.

Leaders of the world's biggest gas suppliers ended their first summit on Tuesday by reiterating the need for a fair gas price while Iran, whose president was absent, warned that Western taxation will derail the energy market.

The 12-member Gas Exporting Countries Forum (GECF) expressed in a declaration they issued after the one-day summit "the need to reach a fair price for natural gas based on gas to oil ... prices indexation."

Nigeria was on high alert Monday after the United States warned of fresh attacks following a wave of deadly blasts claimed by Islamists killed 150 people in the northeast of the country.

Friday's attacks in the city of Damaturu were among the deadliest ever carried out by Boko Haram, an Islamist sect based in the north of Africa's most populous country.

Nigeria marked the Muslim feast of Eid el-Adha amid fears and tears as the U.S. warned of possible new attacks after deadly blasts claimed by Islamists killed 150 people in the northeast of the country.

The attacks on Friday in Damaturu were among the deadliest ever carried out by Boko Haram, an Islamist sect based in the north of Africa's most populous country.