The Muslim Brotherhood's Mohammed Mursi has claimed victory in Egypt's divisive race for the top job, as a military power grab overshadowed the country's first post-Mubarak presidential election.

Two generals from the Supreme Council of Armed Forces (SCAF), however, reiterated that the ruling body would transfer power to the new president by 30 June, and insisted he will enjoy full presidential powers.

State media reported that initial counts showed Mr Mursi ahead.

A confirmed win for Mr Mursi would mark the first time Islamists have taken the presidency of the Arab world's most populous nation, but military moves that appeared to render the post toothless were slammed by activists as a coup.

Representatives of Mr Mursi's rival Ahmed Shafiq, a former air force chief and ex-prime minister under ousted president Hosni Mubarak, disputed the Brotherhood's victory claim, calling it an "act of piracy."

"After the counting was finished in all of Egypt's 27 provinces, indications show that Mohammed Mursi has won 51% and Ahmed Shafiq won 49%," the state-owned Al-Ahram newspaper said on its website.

There were scenes of jubilation at Mr Mursi's Cairo headquarters, where the candidate thanked voters in brief remarks after the Brotherhood said he had secured 52% of the ballots cast.

Mr Mursi pledged to work "hand-in-hand with all Egyptians for a better future, freedom, democracy, development and peace."

"We are not seeking vengeance or to settle accounts," he said, adding that he would build a "modern, democratic state" for all Egyptians, Muslims and Christians alike.

Mr Shafiq campaign officials refused to concede victory, saying their figures showed their man was ahead.

"It's a stolen victory because you can't claim to have won a presidential election while the polling stations are still closing," Mr Shafiq campaign manager Ahmed Sarhan told reporters.

Official results are not expected until Thursday.