A French family of seven kidnapped by Islamic extremists in Cameroon in February have been freed and are in the hands of officials in the central African state, President Paul Biya said.

Biya made the announcement in a statement read on national radio which said the hostages -- a father, mother, four children aged 5 to 12, and an uncle -- had been "handed over last night to Cameroonian authorities.”

Nigerian Islamists stormed a police station in the restive northeast on Thursday, sparking a shootout that left four officers and five insurgents dead, police said.

The overnight attack happened in the remote Babban Gida village of Yobe state, an area repeatedly targeted by Boko Haram, the Islamist group blamed for killing hundreds in northern and central Nigeria since 2009.

The leader of Nigeria's radical Islamist group Boko Haram has rejected the idea of any potential amnesty deal, which the country's presidency said it would study in a bid to curb a bloody insurgency, in a statement obtained by Agence France Presse Thursday.

Abubakar Shekau, the purported head of Boko Haram who has been designated a global terrorist by the United States, claimed his group had "not committed any wrong to deserve amnesty."

A speeding and overloaded bus crashed into a truck parked by a road in northern Nigeria on Monday, killing 20 passengers, an official and a hospital source told Agence France Presse.

The bus had set off from Nigeria's second city of Kano and was headed to Potiskum, the commercial capital of Yobe state.

Weekend attacks on three communities in volatile and ethnically divided central Nigeria have left 19 people dead and displaced some 4,500 others, a local official said on Tuesday.

"From the death toll we've compiled, 19 people including women and children were killed by gunmen we suspect to be Fulani herdsmen in attacks on three communities on Saturday night through Sunday," local government official Kumai Badu told Agence France Presse of the violence in the Kaura district, a remote area of Kaduna state.

Pope Francis prayed for "reconciliation" on the Korean peninsula in his first Easter Sunday message in front of a crowd in St Peter's Square.

Latin America's first pontiff also issued an appeal for hostages held by militants in Nigeria and condemned human trafficking as "the most extensive form of slavery in this 21st century".

A Briton abducted last week in Nigeria's economic capital Lagos has been released in an incident believed to be a ransom kidnapping, police and the British government said Thursday.

"The man was released on Tuesday night," Lagos police spokeswoman Ngozi Braide told Agence France Presse, though the British government said he was freed on Wednesday.

Three Lebanese have been kidnapped in Lagos, a rare case of expatriate kidnapping in Nigeria's commercial center, the state-run National News Agency reported Wednesday.

NNA said the Lebanese foreign ministry was informed about the kidnapping, adding that contacts are underway to set them free.

Twenty-five people were killed in eastern Nigeria when attackers blasted a jail, a police station and a bank with bombs, machine-guns and rocket-propelled grenades, police said Saturday.

"We have 25 dead from yesterday's attacks in Ganye, which included a chief prison warder, a policeman and a prominent politician," said Adamawa state police chief Mohammed Ibrahim.

A Nigerian Islamist group warned against the use of force to free a French man and six members of his family kidnapped in Cameroon in a video aired on Thursday.

Tanguy Moulin-Fournier was kidnapped on February 19 along with his wife, four children aged between five and 12, and brother while vacationing in northern Cameroon.