Eleven people were killed on Wednesday when two girls blew themselves up in twin attacks in northern Cameroon, a region repeatedly targeted by Nigeria-based Boko Haram jihadists.

The assault is the second of its kind in the area in the past 10 days, despite a major regional offensive against the Boko Haram insurgents which still poses a major security threat as it steps up its attacks in the restive Lake Chad region.

Nigeria's President Muhammadu Buhari warned Washington on Wednesday that a U.S. refusal to arm his troops because of "so-called human rights violations" only helps Boko Haram.

The 72-year-old former general has been warmly received in the U.S. capital on his first visit since his March election raised hopes of reform in Africa's troubled giant. 

Suspected Boko Haram gunmen have raided the village of Nigeria's army chief in northeast Borno state, killing two residents and setting fire to several homes, residents said Tuesday.

Dozens of Boko Haram fighters stormed Buratai, the native village of chief of army staff Major General ‎Tukur Yusuf Buratai, ‎around 7:00 pm (1800 GMT) on Monday night, shooting indiscriminately and forcing residents to flee into the bush.

Six new wheelchairs are lined up near the entrance of the Beautiful Gate Handicapped People's Centre in the central Nigerian city of Jos.

The chairs' new owners -- all of them polio survivors -- crawl one by one to the three-wheeled machines with flip-flops on their hands, dragging atrophied, twisted legs and feet behind them.

A refugee camp deep inside Cameroon is receiving around a hundred people each day who are fleeing Islamist violence in Nigeria, the U.N. High Commissioner for Refugees (UNHCR) reported Tuesday.

Families are leaving unstable and dangerous zones on the Nigeria-Cameroon border "and seeking shelter some 100 kilometers (62 miles) inland at the Minawao camp," run by UNHCR and its partners, spokesman Leo Dobbs said.

Three police officers were killed in a bomb blast during a vehicle search at a checkpoint outside the northeast Nigerian city of Damaturu on Monday, police and a witness said,

Yobe state police spokesman Toyin Gbadegesin told AFP initially that two officers were among eight people who died, including two bombers.

Barack Obama will welcome Nigeria's freshly elected president to the White House Monday, lending a personal endorsement after the country's first ever democratic transition.

Obama's administration has faced criticism for not including the continent's most populous country on a Africa tour later this week that will take in Kenya and Ethiopia.

Nigeria's domestic intelligence agency says it has raided several properties belonging to the country's former national security adviser to prevent "treasonable felony", a charge that can include plotting to overthrow the government.

The Department of State Security (DSS) said last Thursday's raids were based on "credible intelligence" linking Mohammed Sambo Dasuki -- who lost his job last week when President Muhammadu Buhari sacked the military top brass -- to "alleged plans to commit treasonable felony against the Nigerian State".

Boko Haram jihadists killed 16 civilians in an attack this week on a southeast Niger village, near the Nigerian border, a local official said Saturday.

"On July 15, Boko Haram elements fired on locals who were praying in a village near the town of Bosso," said Bako Mamadou, mayor of Bosso, a town in southeast Niger on the border with Nigeria, where the armed Islamist group originated.

Chadian troops killed 19 insurgents after Boko Haram attacked an army post on the fringes of Lake Chad, a Chadian security source said, adding a Chadian soldier was also killed in the shootout.

"Boko Haram attacked the post of Konguia at around five in the morning," the source said, speaking on condition of anonymity.