Written by By Steve McAnon, CNN

The Cameroonian government is "verifying" reports that at least 17 people died in a pre-dawn attack in the country's Far North region, UN human rights spokesman Rupert Colville said Monday.

The attack, which took place near the town of Waza, "appears to have been well planned and targeted" during the attack, Colville said.

"Fourteen children, aged between eight and 12, were among the victims, while four attackers were killed," he said. The rest of the casualties were two police officers and three civilians.

The Cameroonian military confirmed it had launched an air strike on Boko Haram fighters who attacked a military outpost at Waza early Sunday, killing two soldiers.

"The Cameroonian government is verifying the bodies recovered by search and rescue personnel so that we can ascertain the true scale of the attack," Colville said.

CNN has also been unable to reach Far North region spokesman Alioune Tine for comment.

In a statement, the Government of Cameroon also said that Boko Haram fighters previously attacked government structures at Waza on October 29, 2016, and "left the town fully looted."

The attack comes as a "serious challenge to the recovery of the region" after three years of violence in the country's far north, Colville said.

More than 2.7 million people have been displaced in Cameroon since 2011 when Boko Haram militants began carrying out attacks in the country, according to the UN Refugee Agency, which estimates that between 1.5 million and 2 million people have been affected by the militant group's violence.

Humanitarian organizations are "seriously concerned" about the conditions in the region, Colville said.

U.N. children's agency (UNICEF) called on Saturday for international donors to increase their funding to communities affected by the violence in Cameroon's far north.

"With one of the highest rates of attacks against children in the world, those affected in Cameroon need immediate help to rebuild their lives," says Param-Preet Singh, UNICEF's regional director for West and Central Africa.

"Children need supplies, support and education now," she said.

Boko Haram was founded in Nigeria in 2002, and has carried out hundreds of attacks across the country and into neighboring states over the past 12 years.