KAMPALA, Uganda (AP) — A tourist from Britain, another from South Africa and their local guide were killed in an attack on a tourist vehicle near a Ugandan national park, according to wildlife authorities.

Unknown assailants set the victims’ vehicle ablaze Tuesday along a road by Queen Elizabeth National Park, located in a remote area of southwestern Uganda near the Congo border. The park is one of the most popular conservation areas in the east African country.

Attacks within and around national parks are rare in Uganda, with specialist police units deployed there.

Ugandan police, in a statement, blamed the attack on the Allied Democratic Forces, or ADF, a shadowy rebel group with ties to the Islamic State.

Ugandan troops are currently hunting down the ADF deep inside Congo. Ugandan authorities say hundreds of ADF rebels have been killed in airstrikes in recent months.

Thomas Tayebwa, deputy speaker of the national assembly said on social platform X, formerly known as Twitter, that the attack “is barbaric and must be condemned in the strongest terms possible.”

The ADF originated in Uganda but later 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 such attack in June, the group was accused of massacring at least 41 people, most of them students, in a raid on a remote Ugandan community near the border.

The ADF has long opposed the rule of Ugandan President Yoweri Museveni, a U.S. security ally who has held power in the East African country since 1986.