Other students have been abducted and a dormitory in the school has been set on fire in the attack, believed to have been carried out by Ugandan militants with ties to the Islamic State group.

The mayor of Mpondwe, the town where the attack took place, near the border with the Democratic Republic of Congo, said 41 bodies have so far been recovered, including 38 students.

Selevest Mapoze said that while some of the students had suffered fatal burns in the dormitory fire, others had been shot or hacked with machetes.

One guard and two members of the local community were also shot and killed outside the school, he said.

Joe Walusimbi, a representative of Uganda's president, said some of the victims "were burnt beyond recognition".

According to Ugandan police, the raid was carried out by the Allied Democratic Forces (ADF), who have been launching attacks from their bases in the DRC for years, targeting civilians.

Officers said Ugandan troops tracked the attackers into Congo's Virunga National Park.

The military confirmed in a statement that its forces "are pursuing the enemy to rescue those abducted".

Influential politician Winnie Kiiza condemned the "cowardly attack" on Twitter.

She said "attacks on schools are unacceptable and are a grave violation of children's rights", adding that schools should always be "a safe place for every student".

The ADF has long opposed the rule of Ugandan President Yoweri Museveni, a US security ally who has been in power since 1986.

The group was established in the early 1990s by some Ugandan Muslims, who argued they had been sidelined by Mr Museveni's policies.

At the time, the rebels staged deadly attacks in Ugandan villages as well as in the capital, including a 1998 attack in which 80 students were massacred in a town not far from the scene of the latest attack.

A Ugandan military assault later forced the ADF into eastern DRC, where many rebel groups are able to operate because the central government has limited control there.

The group has since established ties with IS.

In March, at least 19 people were killed in the DRC by suspected ADF extremists.

Ugandan authorities have long vowed to track down ADF militants even outside the country's borders.

In 2021, Uganda launched joint air and artillery strikes in the DRC against the group.