The two-time Olympic gold medallist Haile Gebrselassie has announced he is enlisting in the Ethiopian military to fight an insurgency that threatens the capital, Addis Ababa. Gebrselassie, who set 27 long-distance running records, told Reuters he was joining up on Wednesday. The Olympic silver medallist runner Feyisa Lilesa would also enlist, local media reported. International alarm has grown over the escalating war in Ethiopia as Tigrayan rebels edge closer to Addis Ababa. On Wednesday, Switzerland and Britain advised their citizens to leave Ethiopia, citing the worsening security situation. France and the US have already called on citizens to leave. Britain’s minister for Africa, Vicky Ford, said the conflict was deteriorating quickly. “In the coming days we may see the fighting move closer to Addis Ababa, which could severely limit options for British nationals to leave Ethiopia,” she said. The country’s prime minister, Abiy Ahmed, has gone to direct the war from the frontlines, state-affiliated media reported. His government has described the conflict as an “existential war”. While Abiy is away, the deputy prime minister, Demeke Mekonnen Hassen, will take charge of routine government business, the government spokesperson Legesse Tulu told a news conference, according to a report from the Fana news outlet. Last month Tigrayan forces and their allies threatened to march on Addis Ababa. They have also been fighting to try to cut a transport corridor linking landlocked Ethiopia with the region’s main port in Djibouti. On Tuesday, the US special envoy for the Horn of Africa, Jeffrey Feltman, said the Ethiopian military and regional militias had held back Tigrayan attempts to cut the corridor, but Tigrayan forces had been able to move south towards the Addis Ababa. Ethiopia’s military spokesperson did not respond to requests for comment. Ethiopian police have trained about 147,000 civilians in the capital to form neighbourhood defence groups and help detect possible infiltrators, police said. Feltman, along with the former Nigerian president turned African Union envoy Olusegun Obasanjo, has been trying to broker a ceasefire between the two sides. On Tuesday, Feltman said nascent progress risked being overshadowed by military developments. On Wednesday, Ethiopia expelled four of six Irish diplomats because of Ireland’s stance on the conflict, the Irish foreign minister, Simon Coveney, said. Ireland has been at the forefront of calling for meetings of the UN security council on Ethiopia and pushing for council statements on the conflict since it joined the 15-member body in January. “Ireland has been shining a spotlight on things that have been happening in Ethiopia that really are breaches of international law and are of serious humanitarian and human rights concern,” Coveney told Ireland’s RTÉ radio. “We’ve already had unfortunately a lot of death and a lot of killing in Ethiopia this year, but it could get an awful lot worse in the next few weeks … and that is why, unfortunately, the Ethiopian government has decided to target Ireland.” Dina Mufti, the spokesperson for the Ethiopian ministry of foreign affairs, did not immediately respond to a request for comment. The Irish foreign ministry said its embassy would remain open but it had asked its citizens to leave by commercial means immediately, and said those planning to visit should reconsider.