State media early Saturday morning declared Mahmoud Ahmadinejad the winner of Iran's presidential election.

However, his challenger and former premier Mirhossein Mousavi alleged irregularities and claimed victory for himself, according to a report in our sister publication, the Gulf Daily News.

The state election commission said Ahmadinejad was ahead with almost 66 per cent of the votes after 21 million votes or 61 per cent of all ballot boxes were counted. Mousavi had nearly 31pc.

The official news agency IRNA said: 'Dr Ahmadinejad, by winning most votes at the 10th presidential election, has secured his victory.'

Mousavi had earlier tried to pre-empt official announcements by calling a news conference at which he alleged there had been irregularities, including a shortage of ballot papers.

The messy and tense outcome capped a long day of voting - extended for six hours to accommodate a huge turnout.

Security officials warned they would not tolerate political gatherings or rallies before the final results were known.

Iranians all over the world also cast their votes, including in Bahrain.

In Washington, US President Barack Obama held out the 'possibility of change' in US-Iran ties but his administration insisted Iran halt its sensitive nuclear work no matter who wins the election. 'We are excited to see what appears to be a robust debate taking place in Iran,' he said.

Ahmadinejad, 52, was poised for a second four-year term, while the 67-year-old Mousavi had hoped to make a comeback after two decades in political wilderness, pledging better ties with the outside world.

A campaign organiser for Mousavi said about a dozen Ahmadinejad supporters attacked one of his campaign offices in Tehran with tear-gas. Mousavi's supporters also clashed with police in Tehran. – TradeArabia News Service