Egypt's former military chief appeared well on his way to a landslide victory over his sole opponent, according to partial election results.

They were announced late yesterday, after voting was extended for a third day in an attempt to prevent an embarrassment over low turnout.

The campaign of retired field marshal Abdel-Fattah el-Sissi said he won 10.35 million votes after nearly half the ballots were counted, with left-wing politician Hamdeen Sabahi taking 333,566.

Mr el-Sissi's win was never in doubt, but the 59-year-old career infantry officer had hoped for a strong turnout to bestow legitimacy on his ousting last July of Egypt's first freely elected president, the Islamist Mohammed Morsi.

However, Mr el-Sissi's campaign said turnout nationwide was around 44%, even after voting was extended for a third day yesterday - well below the nearly 52% won by Mr Morsi.

In his final campaign TV interview last week, Mr el-Sissi set the bar even higher, saying he wanted more than 40 million voters to cast ballots - a turnout of more than 80% - to "show the world" the extent of his popular backing.

Mr el-Sissi supporters began celebrating in Cairo, with several thousands gathered at the central Tahrir square, birthplace of the 2011 uprising that toppled long-time autocrat Hosni Mubarak.

There were smaller crowds in two other Cairo districts and in a string of towns across much of the country.

Critics said the lack of enthusiasm at the polls was in part due to apathy among even el-Sissi supporters, knowing that his victory was a foregone conclusion.

Others said it shows discontent with Mr el-Sissi, not just among his Islamist foes but also among a broader section of the public that believes he has no concrete plans for Egypt's woes and fears he will return Egypt to the autocratic ways of Mr Mubarak.

The tepid turnout was particularly embarrassing because the government and media had been whipping up adulation for Mr el-Sissi over the past 10 months, depicting him as a warrior against terrorism and the only person able to tackle Egypt's economic problems, high unemployment and inflation.

His supporters in the Egyptian media have been in a panic the past two days. Political talk show hosts and newscasters urged people to vote, warning that otherwise the Muslim Brotherhood will be encouraged to step up its challenge to the new government.

The abrupt decision by the election commission to add another day of voting raised complaints that authorities were tipping the playing field in Mr el-Sissi's favor.

US-based Democracy International, which had been observing the vote, said the extension "raises more questions about the independence of the election commission, the impartiality of the government, and the integrity of Egypt's electoral process".

Mr Sabahi, Mr el-Sissi's only opponent in the race, protested against the extension, saying it aimed to "distort" the will of the people.

His campaign pulled its representatives from polling stations yesterday in protest against what it called a campaign of intimidation and arrests of its campaign workers.

Mr Morsi's Brotherhood supporters and other Islamists boycotted the vote and scattered protests by Morsi supporters were quickly dispersed by security forces.

In Fayoum, south-west of Cairo, riot police fired tear gas after protesters hurled stones while marching and chanting slogans against elections.