"UK armed forces have completed a complex and rapid evacuation of British diplomats and their families from Sudan, amid a significant escalation in violence and threats to embassy staff," Sunak tweeted.

The prime minister said the government was "continuing to pursue every avenue to end the bloodshed in Sudan and ensure the safety of British nationals remaining in the country".

Defence mininster Ben Wallace tweeted that UK forces undertook the military operation alongside "the US, France and other allies".

The UK operation involved more than 1,200 personnel from the army, the Royal Marines and the Royal Air Force, he added.

Ferocious battles between the Sudanese army and a paramilitary group -- which has seen fighting with tanks in densely populated Khartoum and air strikes launched by fighter jets -- have killed more than 400 people and left thousands wounded.