‘Irregularities in Iran presidential run-off'

However the Guardians Council, an unelected hardline-controlled political watchdog, dismissed the complaints and effectively vetoed any move to halt the high-stakes election.

"We have received a number of reports concerning interference in certain polling stations from people who shouldn't be there," the reformist-controlled interior ministry's spokesman Jahanbakhsh Khanjani told reporters.

Iranians were voting in a tight presidential run-off between moderate cleric Akbar Hashemi Rafsanjani and hardliner Mahmood Ahmadinejad.

Rafsanjani and two beaten reformist candidates have already alleged Ahmadinejad is being backed illegally by well-financed regime elements such as the Guardians Council, the Basij militia and Revolutionary Guards.

"The reports from inspectors, particularly in Tehran, show that violations have gone beyond what could be considered a small level," Khanjani said.

"The interior ministry is examining the possibility of suspending operations in certain polling stations," he warned.

But the Guardians Council, whose 12 members are appointed by supreme leader Ayatollah Ali Khamenei and which has veto power over the interior ministry, dismissed the fresh allegations.

"Certain people are trying to disturb the election by diffusing false information," Guardians Council spokesman Gholamhossein Elham told the student news agency ISNA.

"We have not received any reports of irregularities that could damage the electoral process. No organ has the right to stop the vote and any such move can be followed up by the judiciary," he warned.