Iranian President Mahmoud Ahmadinejad has suffered further embarrassment as his third nominee for the key post of oil minister was rejected by MPs.
Mohsen Tasalloti's loyalty to the Islamic republic was questioned
Mohsen Tasalloti, the director of a petrochemical development zone in southern Iran, was dogged by rumours about his personal life and fortune.
The Majlis rejected the president's first two nominees for lacking experience in the oil sector.
Iran is the world's fourth biggest producer of crude oil.
Nearly two-thirds of the MPs present voted against the president's candidate in a session.
The BBC's Tehran correspondent, Frances Harrison, says parliament's rejection of three candidates over the past few months is an unprecedented challenge and a huge embarrassment to the new president.
Lawmakers had questioned Mr Tasalloti's loyalty to the Islamic republic.
He has denied claims that he has a US green card residency permit and that his daughter is a British citizen.
Mr Tasalloti was also accused of having supported reformist candidate Mostafa Moin in the last presidential election.
On Tuesday, the central council of the Majlis majority faction voted against him, indicating opposition even among some supporters of the president, our correspondent says.
This forced Mr Ahmadinejad to defend his nominee in a last-ditch attempt to gain approval.
"The government respects the choice of parliament, but unjustly accusing a brother on an unknown internet site... is not fair," he said.
After the last vote, Mr Ahmadinejad said no government since the Islamic revolution in 1979 had been attacked so viciously as his.