Twenty people arrested on suspicion of collaborating in Uganda school massacre

Twenty people accused of helping an ISIS-linked rebel group suspected of killing dozens, mostly students at a school in western Uganda, have been arrested, Ugandan police told CNN.

Around 42 people, including 37 students were killed on Friday when members of the Allied Democratic Forces (ADF) rebel group attacked the Lhubirira Secondary School in Mpondwe, hacking some of their victims to death with machetes and setting off fire at the dormitories.

Six other people were abducted, authorities said.

A spokesperson for the Uganda Police Force, Fred Enanga, told CNN on Monday that 20 suspected ADF collaborators had been arrested, but no actual members of the militia group.

The arrests follow authorities' earlier disclosure that the ADF may have spent days planning the attack with the help of local residents in town.

The Lhubirira school is located in the town of Kasese, which sits along the country's border with the Democratic Republic of Congo, with students aged between 13 and 18.

The youngest victim in the Friday attack was just 12 years old, police said.