Iranian President Mahmoud Ahmadinejad flashes a victory sign with an ink-stained finger as he holds up his identity cards at a Tehran polling station on June 12, 2009.

Iranian state media say Mahmoud Ahmadinejad has won re-election as Iran's president, but a reformist rival also is claiming victory.

Election officials say Ahmadinejad has won 67 percent of the vote to 30 percent for Mousavi, a former Iranian prime minister. The tally is based on results from nearly 50 percent of the ballots. Mousavi claimed victory late Friday at a news conference in Tehran. He also said there were problems with the voting process because of a shortage of ballots in some areas.

Iran's election Friday appeared to be a tight race between Ahmadinejad, the conservative incumbent, and Mousavi, the leading reformist candidate. Iranians lined up to vote in massive numbers for the election. Officials extended voting hours repeatedly to accommodate long lines. Large crowds were still waiting outside many polling stations at closing time, 10 p.m. local time. Officials said anyone already in line would be allowed to vote.

An Iranian clergyman shows his ink-stained finger after voting in the Shiite holy city of Qom on June 12, 2009.

Election commission chief Kamran Daneshjou said turnout was "unprecedented."  Officials predicted a turnout of 70 percent or more of Iran's 46 million eligible voters.

Reformist cleric Mehdi Karroubi and conservative former Revolutionary Guards commander Mohsen Rezaei also competed in the poll, in which Iran's economy, nuclear program and foreign relations were said to play a key role. Mousavi urged election officials to comply with the law Friday, after some of his representatives were reported to have been blocked from entering polling stations to monitor the voting. 

Ahmadinejad's rivals have accused him of badly mismanaging the economy and tarnishing Iran's image, further isolating the country from the West.

Analysts expected a close race. If no candidate wins an outright majority, the two leading candidates will face each other in a run-off vote on June 19.

Some information for this report was provided by AFP, AP and Reuters.