Boko Haram fighters torched a village in Cameroon's troubled Far North Region overnight and killed 11 civilians in their sleep, security sources told AFP on Friday.

Cameroon opposition leader Maurice Kamto, who claims to have been cheated out of the presidency in elections last year, was arrested in the country's economic capital Douala on Monday, a senior party member said.

Three civilians were killed and around 20 others wounded on Sunday in a suicide attack in northern Cameroon, officials and a vigilante group said.

Cameroon mounted a major assault against a key Boko Haram base in Nigeria last week, inflicting heavy losses on the Islamist group and seizing arms and prisoners, the government said in a statement obtained by AFP on Tuesday.

The Cameroonian army offensive took place from February 11 to 14 in Ngoshe in Nigeria, some 15 kilometers (nine miles) from the northern town of Ashigashia on the border between the two countries, government spokesman and Communications Minister Issa Tchiroma Bakary said in the statement.

At least 26 people were killed on Monday when three suicide bombers blew themselves up at a market in the far north of Cameroon, a region often targeted by Nigeria's Boko Haram.

Police said the assailants hit a local market in Bodo village near the frontier with Nigeria in one of the most deadly attacks in the Far North since 2013.

At least seven civilians were killed Friday in a suicide attack in Kolofata, northern Cameroon, a region where Nigeria's Boko Haram Islamists are highly active, local officials said.

"We've registered eight deaths at the site, including the suicide bomber," a regional security source said without saying if the attack on a food stall was carried out by a man or a woman.

Cameroon troops killed around 100 Boko Haram Islamist fighters from Nigeria, freed almost 900 hostages and seized Islamic State (IS) flags last week, the defense ministry said Wednesday.

"A special clean-up operation from November 26 to 28" against Boko Haram fighters in the border area with Nigeria "neutralized more than 100 jihadists", Defense Minister Joseph Beti Assomo said in a statement broadcast on national radio.

Three people died in a fresh attack on a mosque by two women suicide bombers Monday in northern Cameroon, a region repeatedly targeted by Boko Haram Islamists, residents and security sources said.

"A (woman) kamikaze blew herself up near a mosque in Fotokol. A second one was neutralized and killed. It was obvious the two suicide bombers were targeting the mosque," a local source told AFP.

In the poverty-stricken far north of Cameroon, the priority is the fight against the Nigerian militants of Boko Haram, but experts say a growing humanitarian crisis also needs urgent attention.

Chased from their strongholds in northeast Nigeria by a multi-national army offensive, the insurgents of Boko Haram have increased the tempo of suicide attacks and bloody raids on neighboring Cameroon despite the deployment of a huge military contingent along the border.

Two young suicide bombers killed three people in far north Cameroon on Sunday, the latest attack to hit a region that has been rocked by strikes blamed on Boko Haram Islamists from neighboring Nigeria.

The youth set off their suicide belts in the town of Mora as a police officer became suspicious of their appearance and approached to question them, a security source said on condition of anonymity.