A suspected 12-year-old girl suicide bomber killed 20 people in an attack on a bar in Maroua in the far north of Cameroon, state television said Sunday, just days after 13 died in twin bombings in the city blamed on Boko Haram.

The bomber blew herself up among Saturday night revellers in the popular bar, injuring at least 79 others, state TV reported. An earlier toll put the number of dead at 14.

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.

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.

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.

A northern region of Cameroon, which has suffered frequent attacks by the jihadist Boko Haram group, has banned the use of the full Islamic veil, governor Bakari Midjiyawa said Thursday.

"The full veil is completely forbidden" in the Far North region, where two women suicide attackers who were wearing the covering killed 11 people on Sunday, Midjiyawa told AFP.

At least 11 people were killed when two female suicide bombers blew themselves up near an army camp at Fotokol in troubled northern Cameroon, a local security source said Monday.

A police source in the region confirmed a double attack had taken place on Sunday but was unable to give a precise death toll.

An international human rights group demanded Friday the release of 84 Cameroonian children detained illegally for the last six months after the security forces raided their Koranic schools.

Most of the children are under 15 years old, with some as young as five.

Nigeria's new President Muhammadu Buhari will this week make his first foreign trip since taking office, traveling to Chad and Niger for talks on Boko Haram, his spokesman said on Monday. 

Shehu Garba said the two-day trip starting on Wednesday will focus on "matters of security", with the cooperation of Nigeria's neighbors seen as crucial to ending the Islamist uprising which has claimed more than 15,000 lives since 2009. 

Nigeria's military on Saturday repelled a Boko Haram attack on the key northeastern city of Maiduguri, a day after President Muhammadu Buhari took office vowing to crush the group, witnesses and security sources said.

The overnight attack on the Borno state capital saw rocket-propelled grenades fired into homes in a bombardment that reportedly lasted several hours.

A fundraising campaign to help Cameroon's army battle Nigeria's feared Boko Haram fighters has brought in more than three million euros and hundreds of tonnes of food, local media said Wednesday.

"2.1 billion CFA francs (3.2 million euros) already" collected to help troops fighting the Islamist group on Cameroon's northern border with Nigeria, said the national CRTV radio and TV network.