British nationals trying to flee Sudan have until noon to reach an airport to be processed for an additional UK flight out of the conflict zone as rescue efforts shift to the east of the country.

Members of the military are working round the clock to assist UK citizens and others trying to escape the war-torn nation amid an uneasy ceasefire, the Foreign, Commonwealth and Development Office (FCDO) said.

Some 2,122 people on 23 flights have been evacuated from the Wadi Saeedna airfield near Khartoum but more than 1,000 British passport holders may remain.

The Government announced on Friday it was ceasing operations from the site on Saturday as an armistice between the country’s warring generals appeared to start breaking down.

UK citizens are now being advised to travel to Port Sudan where an extra flight will take off on Monday, the FCDO said, as warring factions agreed to extend the fragile ceasefire for a further 72 hours.

In order to be processed for the journey, people are being urged to arrived at the city’s international airport before midday local time.

It is understood the flight from Port Sudan is exceptional and would repatriate a limited number of British nationals left in the country who wish to leave.

Foreign Secretary James Cleverly said: “Evacuation flights have ended from Wadi Saeedna but our rescue efforts continue from Port Sudan.”

The armed forces and border force staff have been supporting the FCDO with the evacuation mission, with HMS Lancaster and the RAF redirected to the area.

The UK will continue to advocate for a long-term end to the conflict along with its international allies, Mr Cleverly said.

The British Government has agreed to include NHS doctors without UK passports on its final journeys amid criticism over the scope of its eligibility criteria for evacuation.

Flights had previously been limited to British nationals and their immediate family.

But its decision not to offer escorts to those making the potentially perilous journey to the airfield near Khartoum was also called into question.

Flights have been touching down in Cyprus, which has activated a humanitarian rescue mechanism for evacuating third-country civilians, before arriving in the UK hours later.

Fighting has broken out again in Khartoum despite a truce having been brokered last week.

The conflict pits army chief General Abdel Fattah Burhan against General Mohammed Hamdan Dagalo, the head of a paramilitary group known as the Rapid Support Forces (RSF).

The generals, both with powerful foreign backers, were allies in an October 2021 military coup that halted Sudan’s fraught transition to democracy, but they have since turned on each other.