The ballot papers processed at the central tally centre represent 55 percent of the Ugandan electorate and come from 92 percent of polling stations, Kiggundu said.He did not reveal a turnout figure but when asked whether if Museveni could still mathematically be forced into a second round, another electoral board official: "It seems impossible."

The veteran leader's main rival Kizza Besigye who has complained of widespread irregularities before, during and after polling had only garnered 26.28 percent of the vote at the same stage of tallying.The electoral commission acknowledged some minor irregularities but insisted they had been dealt with and full official results were expected to be announced within hours.Poll observers from the Commonwealth and European Union were expected to present their preliminary findings later Sunday.

Besigye, the most prominent of Museveni's seven challengers, vowed beforehand that only rigging could deprive him of victory and accused the electoral body of being partial."It is now clear that the will of the people cannot be expressed through the electoral process," he told AFP on Saturday.Besigye added however that he would convene a meeting with his top advisers on Sunday to decide on the best course of action for his movement.

Parallel counting conducted in a secret tallying centre by a small army of number-crunchers Besigye recruited from his Inter-party Conference (IPC) opposition coalition before the vote gave Museveni a much narrower lead.But with only a fraction of the returns from polling stations trickling into the shadow centre, Besigye's parallel tallying appeared to have backfired as even his partial results gave Museveni 62 percent of the vote.

Polls opened late in some parts of the capital Kampala, which voted against Museveni in the 2006 elections, prompting opposition claims that the president was trying to cheat his way to re-election.Some 14 million voters, out of a total population of just under 33 million, were called to choose their next president and members of parliament on Friday.

Museveni now looked assured of extending his rule by five years, joining Libya's Moamer Kadhafi and Zimbabwe's Robert Mugabe, among others, in a club of African leaders who have ruled more than 30 years.Opponents of Museveni had warned Uganda was ripe for the kind of uprising currently sweeping the Arab world, raising fears of unrest stemming from yet another post-election dispute on the continent.

"Tunisia", "Egypt" and "Dictator" were on a list of potentially explosive terms the Uganda Communications Commission said it had instructed telecom operators to block in text messages.But Museveni has dismissed any suggestion a wave of popular discontent could rattle his firm grip on east Africa's second economy and polling day passed without major incident or sign of anti-regime mobilisation.

Museveni has campaigned on his success in ridding the country of the Lord's Resistance Army rebels and the prospect of an oil windfall in his next term.