The arrival of European Union forces (EUFOR) to monitor the volatile Chad-Sudan border was set to be delayed as rebels inched to within 50 kilometres of the Chadian capital N'Djamena Friday, reports said, according to dpa. A spokesman for the Irish Defence Forces told Irish national broadcaster RTE that 50 members of the elite Army Rangers were delayed from flying out Thursday evening after reports came in that rebels had sealed off the N'Djamena airport. The Rangers were set to prepare the ground for the 350 Irish troops that are due to join the EUFOR mission to Chad in the middle of March. The Rangers and army engineers are to be based in Abeche, where the EU force will be headquartered. "The deployment (of the troops) can be further delayed," French General Jean-Philippe Ganascia told the daily Le Figaro. Some 3,700 EUFOR soldiers are expected on the Chad-Sudan border, across which refugees from Sudan's conflict-torn western Darfur region continue to pour. A EUFOR spokesman told the BBC the mission did not want to get involved in a country's internal affairs. Citing rebel and military sources, France Inter radio said intense battles broke out at mid-morning at Massaguet, some 50 kilometres north-east of N'Djamena after a column of rebel soldiers crossed the entire country in a matter of days. The website of the weekly Le Nouvel Observateur reported that the head of one of the three main rebel groups, Timan Erdimi, has given Chadian President Idriss Deby until later Friday to open negotiations on power-sharing or there would be a full-blown war. The French government beefed up its military presence in N'Djamena Friday with a company of 150 soldiers from its garrison in Libreville, Gabon, to protect French nationals in the capital. France has had a force of 2,000 in its former colony since 1986. On Thursday, French Defence Minister Herve Morin told US authorities in Washington that France would fulfil its commitments in Chad, which includes logistical and intelligence support for the Chadian military. In April 2006, French fighter jets attacked rebel troops as they marched on N'Djamena. As a result of the fighting, the United Nations refugee agency UNHCR said Friday it had evacuated most of its staff from the area of Guereda in eastern Chad. The UNHCR team in the area said it had experienced several attacks in 72 hours, with gunmen in military uniforms breaking into its compound and threatening the guards with guns. "If humanitarian workers are not around, it is impossible to provide adequate protection to the refugees," said Jorge Holly, head of the UNHCR field office in Guereda. "But the situation here is getting out of control and we also have to protect our staff and partners." UNHCR said few essential staff would remain in the area and camp leaders would assist in providing food and water to the 30,000 refugees there.