KAMPALA, Uganda (AP) — A Ugandan military spokesperson says troops have captured a commander of an extremist group whose fighters are accused of killing two tourists last month.

Col. Deo Akiiki said Wednesday that a senior commander with the Allied Democratic Forces, a rebel whose nom de guerre is Njovu, was in military custody.

Njovu was captured during an exchange of fire on Lake Edward on Uganda’s border with Congo. An unknown number of rebels drowned or were shot in the fighting Tuesday night, according to Akiiki.

Njovu has been in charge of operations such as the murder in October of a South African tourist and her British husband while they were honeymooning in remote Queen Elizabeth National Park. Their Ugandan guide also was killed and their vehicle set on fire.

The ADF has ties to the Islamic State group. Following the attack on the tourists, Ugandan President Yoweri Museveni urged security agencies to ensure the group “is wiped out.”

Ugandan troops are hunting down the ADF deep inside Congo, where the group is among dozens of rebel outfits operating in a large swath of territory. Ugandan authorities say hundreds of ADF rebels have been killed in airstrikes in recent months.

The ADF originated in Uganda but was forced to flee to eastern Congo, where it is accused of carrying out multiple attacks targeting civilians. The group is not known to claim responsibility for attacks it carries out.

The ADF occasionally conducts cross-border attacks. In one attack in June, the group was accused of massacring at least 41 people, most of them students, in a raid on a Ugandan community near the border.