Suicide bombers have killed two people and wounded 11 others at a camp in Niger Republic housing thousands of people who have fled Boko Haram violence in the first suicide attack in the region in a year.

An agency of the United Nations, Human Rights Commissioner for Refugees (UNHCR), said the 2 suicide bombers were women.

According to the agency, the women entered the camp in Kabelawa, around 50 km north of the border with Nigeria, and joined a group of young people before detonating suicide belts just before midnight on Wednesday.

“The explosion killed two young inhabitants of the camp, a male and a female, as well as the two women. 11 others were injured, two seriously,” the UN agency said in a statement.

Boko Haram launches frequent cross-border raids from its strongholds in north-eastern Nigeria in its bid to carve out an Islamic caliphate, though most recent suicide attacks have targeted towns in northern Cameroon.

The group’s eight-year insurgency has killed more than 20,000 people in the Lake Chad region and displaced 2.7 million.

There are over 166,000 refugees living in Niger, as well as 127,000 internally displaced Nigeriens.

To reduce the number of refugees that have entered Cameroon in the heat of the insurgency in Nigeria, the Cameroonian authorities forced 877 refugees to return to Nigeria few days ago.

The UNHCR said the Nigerian refuges “were rounded up at 19:30 (7:30 p.m) local time and forcibly removed to Banki in Nigeria in desperate conditions”.

The agency in a statement on Thursday, however, cautioned against forceful return of refugees.

According to the agency the refugees were repatriated in 6 trucks provided by the Nigerian military and Cameroonian police from the Kolofata border site adding that most of them were children.