Egyptian election officials have failed to confirm the date of the first presidential election since the overthrow of Hosni Mubarak. An election commission briefing only expressed hope the process could be over by the end of May. The commission chairman told local TV the problem lay in organising the expatriate vote. Mr Mubarak stepped down on 11 February last year after 18 days of street protests in which hundreds were killed. The military took over but has faced continuing unrest from protesters demanding an earlier transfer of power. Parliamentary elections have already been held and a new assembly dominated by Islamist parties held its first session earlier this month. Transition pressure The BBC's Jon Leyne in Cairo says confirmation of a date in June had been expected but after a long preamble, the commission only expressed hopes about the timetable. He says the delay suggests there may be a behind-the-scenes battle over the timing of returning to civilian rule. Commission chairman Faruq Sultan said on the Nile News channel that the delay was because of problems organising the vote of Egyptian expatriates and that the foreign ministry had asked for more time. Mr Sultan said nominations for president still had to be in by 10 March and the timetable for polls would be announced before then. According to rules set by a referendum last year, the president will serve for four years and be able to serve two consecutive terms. Earlier, election commission member Ahmed Shams el-Din had told Egyptian media: "The election will start in the first days of June and will end in the last week of June if there is a run-off." The ruling military - the Supreme Council of the Armed Forces (Scaf) - headed by Field Marshal Tantawi, has been under pressure to bring forward the election date to May. But it had warned it would not bow to demands to speed up the transition process, amid democracy activists' threats of a campaign of protests. The Scaf has promised to hand over power after the presidential elections but activists fear it will try to retain its influence. Mr Mubarak is on trial accused of ordering the killing of demonstrators, charges he denies.