The Foreign Office has announced there will be at least one more flight out of Sudan, ITV News' Sam Holder reports
The UK will run an additional evacuation flight from Port Sudan on Monday, the government has announced.
Foreign Secretary James Cleverly said rescue efforts would continue from the east of Sudan as Britain and its international allies advocate for a long-term ceasefire.
Some 2,122 people on 23 flights have been flown out of the war-torn country from the airfield since fighting began but more than a thousand UK nationals may remain.
It comes as Sudan’s army and its rival paramilitary said on Sunday they will extend a humanitarian ceasefire a further 72 hours.
The decision follows international pressure to allow the safe passage of civilians and aid, although it has not stopped clashes continuing to break out.
British nationals who wish to leave Sudan are being asked to travel to the British Evacuation Handling Centre at Port Sudan International Airport on 1 May before noon local time (11am BST) tomorrow.
The British government previously announced it would end evacuation efforts from the capital, Khartoum, with the last flight having taken off from Wadi Saeedna at 10pm local time on Saturday.
The government later agreed to include NHS doctors without UK passports on its final journeys amid criticism over the scope of its eligibility criteria for evacuation.
Ministers answered calls to widen the remit, which had been limited to British nationals and their immediate family, after a significant decline in the number of UK citizens coming forward.
Speaking to the BBC, Foreign Office minister Andrew Mitchell said the operation has been "extremely successful", but stressed: "We can't stay there forever in such dangerous circumstances."
A statement on the government's travel advice site says: "We have established an office at the Coral Hotel in Port Sudan.
"If you are a British National in Port Sudan who needs help to leave Sudan, visit our team who will be able to signpost you to options for departure."
Fighting has broken out again in Khartoum despite the extension of an armistice between the country's two warring generals having been brokered in the early hours of Friday.
Earlier on Sunday, an aircraft carrying emergency medical supplies landed in Port Sudan to resupply the hospitals devastated by more than two weeks of fighting. The supplies, including anesthetics, dressings, sutures and other surgical material, are enough to treat more than 1,000 people wounded in the conflict, the International Committee of the Red Cross (ICRC) said. The civilian death toll reached 425 on Sunday and 2,091 civilians have been wounded, the Sudan Doctors’ Syndicate said. The Sudanese Health Ministry on Saturday put the overall death toll, including fighters, at 528, with 4,500 wounded.
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Thousands of British citizens are still feared to be trapped in Sudan as the UK's evacuation efforts wind down, with families describing feeling "left without support" from the government.
British pensioner Maureen, speaking from the north of Khartoum on Saturday, told ITV News some were too frightened to make the journey to the Wadi Saeedna airbase to be evacuated.
"People don't understand, they think you should take that risk but it's not that easy and I don't feel confident enough to do that," she said.
As she spoke, popping could be heard in the background. Maureen said it was gunfire.
She added: "It's a scary situation, it really is. Until you're in this situation you'll never know and I know people will be thinking 'Oh just get out, go and chance it' but it's not that simple. It really isn't.
"I just pray to God that something will turn for the good."
'I don't know if you can hear the firing now - the shooting'
Another person still in the war-torn country is 7-year-old Mohamed Niyal Hidar Abdullah. He is British through his father, his family says, but he is stuck in Sudan without a passport.
His mother has been trying unsuccessfully to get him on one of the British flights.
"To just get to the airbase is a life-threatening journey because although there are claims of a cease-fire there is no actual ceasefire that's taken hold on the ground," the 7-year-old's cousin, Mohammed Elnaiem, said.
Elsewhere, a mother and father who both work for the NHS missed the last UK evacuation flight from the Wadi Saeedna airfield, believing the journey to be "too dangerous".
Sarra Eljak, 38, her husband Mustafa Abbas, 44, and their four children are sheltering in the city of Wad Madani.
Despite the dangers of being left behind, they said it was too risky to make the journey to the evacuation site with their children Danya, 12, Menna, 11, Anne, seven, and Mohammed, six months.
"It's extremely dangerous to reach the evacuation site and the area is still experiencing attacks," Ms Eljak said on Saturday.
"I can't take this risk with my children. They should consider people with families.
"I don’t want to put my kids' life in danger. I feel like we have been left without support."
Foreign Affairs Committee chairwoman and Conservative MP Alicia Kearns said she had received reports that elements of the Sudanese Armed Forces had blocked some British nationals from accessing the air base ahead of the final departure from Wadi Saeedna airfield on Saturday night.
She told The Observer: "I've had some messages saying the Sudanese Armed Forces have been stopping people from crossing through Khartoum to get to the airstrip.
"I think we need to look into that and see if that’s got any truth to it."
Help and advice
If you are in Sudan you can contact the FCDO 24/7 helpline at +44 1908 516 666
Select option 2 for consular services for British nationals.
If you're in the UK and worried about a British person in Sudan you can call 020 7008 5000.
FCDO advises against travel to Sudan for security reasons. More information can be found on the government website.
If you have not registered your presence in Sudan, you can register here.
You should also check the travel advice for Sudan for the latest guidance.
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