Britain said it had evacuated nearly 900 people from Sudan and was hoping to continue evacuation flights overnight, although violence flared as the country’s warring factions agreed to extend a ceasefire. The foreign secretary was under pressure over a refusal to allow Britons trying to flee to take elderly parents with them, amid fears that renewed fighting between the army and paramilitaries could halt the airlift at any time. James Cleverly told MPs on Thursday that the UK “will endeavour” to keep going with flights, but he advised Britons to try to make a risky journey to the airfield north of Khartoum from where the airlift was being conducted immediately. A total of 897 people had been evacuated by the RAF by 6pm on Thursday, with two more flights leaving Sudan for a stopover in Cyprus during the day. The Foreign Office said “further flights” would be coming. That came ahead of an announcement of a 72-hour extension to a ceasefire that had been due to run out overnight, a decision welcomed by the US, the UK, Saudi Arabia and others hoping to end the fighting between the Sudanese army and paramilitaries. In a joint statement, the allies said they “welcome the announcement by the Sudanese armed forces and Rapid Support Forces (RSF) to extend the current ceasefire for an additional 72 hours and call for its full implementation”. Cleverly urged all UK nationals wishing to flee to hurry to the airport north of the capital, Khartoum. “I urge all British nationals wishing to leave to proceed to the airport as quickly as possible to ensure their safety.” Earlier, a senior Conservative had called on Cleverly to relax the evacuation requirements to allow Britons to take elderly Sudanese parents with them, amid reports that some were refusing to leave infirm mothers or fathers behind. “Children we treat as dependants but very elderly sick parents should also be treated as dependants,” said Alicia Kearns, the chair of the foreign affairs select committee, adding it was not clear whether the Home Office or the Foreign Office was determining the criteria. A British doctor has told the Guardian that her father, a retired 67-year-old doctor who worked for the NHS for more than 30 years, has decided to remain in Sudan despite being shot in the thigh because he cannot take his 87-year-old mother with him. He had been visiting her for Ramadan. “Our primary duty is to traditionally recognised dependants,” Cleverly responded, adding “it would be a real challenge to extend the criteria”. He said he wished instinctively to be as supportive as possible. Britain has been evacuating civilians from the Wadi Seidna airbase north of Khartoum since Tuesday, in a series of flights going via Cyprus to the UK, but it will only pick up British nationals, their spouses and children under 18. Military planners say the airfield is relatively secure under the control of the Sudanese army. “We will endeavour to keep evacuating people … but we cannot guarantee our ability to do so,” Cleverly told MPs. However, the unpredictability of the situation meant that “we are encouraging those who wish to travel to make their way to the airport today”. The minister acknowledged that Foreign Office officials had no means of knowing how many of the 2,000-plus who had registered to leave on UK government flights had in reality taken other routes out of the country. A contingent of Royal Marines is at Port Sudan, 500 miles north-east of Khartoum, ready to help open up a potential new evacuation point. Maritime trackers showed that the frigate HMS Lancaster had arrived at the city to help with a possible rescue if the airlift has to stop. The foreign secretary had earlier called on both sides – the Sudanese army and the paramilitary RSF – to extend the ceasefire, although he acknowledged: “Our ability, as in the case for all outside powers, to determine the course of events inside Sudan is limited.” But he added: “Anyone, if they aspire to be a leader of Sudan, demonstrating a willingness to protect the people of Sudan would be a good starting point.” The UK government has faced criticism about being behind Germany and France in evacuating civilians, and from some Britons caught up in the outbreak of fighting about a lack of communication and planning as they attempt to leave the country. Speaking on BBC Radio 4’s Today programme, Cleverly said: “I understand how frustrating it must be when you are not able to get communication or get updates of what’s happened.” The minister acknowledged mobile phone coverage in Khartoum was inconsistent and UK representatives had been broadcasting messages through social media channels and WhatsApp groups. Asked why other countries, such as Germany, China and the US had evacuated more people, Cleverly said UK nationals were more dispersed than other expatriate communities. But he refused to discuss the possibility of safe and legal routes for non-UK nationals fleeing Sudan to get to the UK. “There is war and conflict all over the world,” he said. “There are literally millions upon millions of people who are in countries plagued by war. We recognise that we cannot host everybody who is in a country plagued by war.”