• Uganda's police said the trio were were killed, and their vehicle burned, in the Queen Elizabeth National Park.
• It said joint forces were pursuing suspected members of the Allied Democratic Forces (ADF) rebel group on Tuesday night.
A British tourist is among three people killed in a "cowardly terrorist" attack at a national park in south-west Uganda, authorities say.
Uganda's police said the trio were were killed, and their vehicle burned, in the Queen Elizabeth National Park.
It said joint forces were pursuing suspected members of the Allied Democratic Forces (ADF) rebel group on Tuesday night.
The Uganda Wildlife Authority said the victims were two tourists and a guide.
The tourists were from the UK and South Africa while their guide was Ugandan, it added.
The ADF is an IS-linked Islamist group which traces its roots to Uganda but operates mainly in the east of the Democratic Republic of Congo. The two countries have intensified operations targeting the group in recent months.
Police spokesperson Fred Enanga said on X, formerly known as Twitter: "We have registered a cowardly terrorist attack on two foreign tourists and a Ugandan in Queen Elizabeth National Park.
"The three were killed, and their safari vehicle burnt."
He added the police are "aggressively pursuing" the suspected rebels, and expressed "our deepest condolences to the families of the victims".
The police force also posted a photograph of a green four-wheel-drive vehicle on fire.
Bashir Hangi, spokesperson for the Uganda Wildlife Authority, said the attack took place on Tuesday evening.
The Uganda Wildlife Authority said in a statement all parks remain open, adding: "We urge the public to remain patient and allow the investigative process to run its course."
The UK Foreign Office has updated its travel advice for the country, warning the "attackers remain at large".
It said: "If you are in the area you should remain vigilant and follow the advice of the local security authorities and/or your tour operator.
"Ugandan authorities have advised anyone in Queen Elizabeth National Park to stay put overnight."