KAMPALA, Uganda (AP) — Two foreign tourists and their Ugandan guide were killed when assailants attacked their vehicle near a national park in southwestern Uganda, a wildlife official said Tuesday.

Bashir Hangi, spokesman for the Uganda Wildlife Authority, said the attackers set on fire the vehicle in which the group was traveling just outside Queen Elizabeth National Park.

The park, located in a remote area near the Congo border, is one of the country’s most popular conservation areas.

Hangi said the Uganda Wildlife Authority and security agencies were working “to establish who could have carried out this heinous act.” He did not provide any more details.

Such an attack is rare in the East African country. It comes at a time when Ugandan troops are hunting down extremist rebels in neighboring Congo. Those rebels occasionally carry out cross-border attacks.