Gunmen ambushed Robert Jesty, Bethan Davies and their driver in Congo’s volatile eastern borderlands on Friday and released them three days later.

Park ranger Rachel Makissa Baraka, 25, was killed trying to defend them.

“The suspension of tourism is being undertaken as an additional precautionary measure whilst an investigation is undertaken surrounding the recent events,” the park said in a statement.

It said the suspension would remain in place until June 4.

Eastern Congo has seen successive waves of violence over the past quarter century and was at the epicentre of two wars between 1996 and 2003 that killed millions, mainly through hunger and disease.

Rebel groups and militias still control large swathes of the territory. More than 175 rangers have died protecting the park, which is in the rugged mountains and volcanic plains adjacent to Rwanda and Uganda.

Since tourism was relaunched in 2014, Virunga National Park - Africa’s oldest national park - has received more than 17,000 visitors, keen to see its rare mountain gorillas or climb the active Nyiragongo volcano.