Manssor Arbabsiar, 56, who was arrested on Sept. 29 in New York, faces several charges including conspiracy to murder a foreign official, conspiracy to use a weapon of mass destruction and conspiracy to commit an act of terrorism.

Another man, Gholam Shakuri, was also charged in the plot but is believed to still be in Iran. US officials said he is a member of Iran’s Quds Force, the covert operations arm of the country’s powerful Islamic Revolutionary Guard Corps.

US prosecutors accused the two men of planning to assassinate the Saudi ambassador to the United States, Adel Al-Jubeir, by planting a bomb in a Washington restaurant. The Iranian government denies any involvement.

But details such as Arbabsiar’s bumbling nature and his trust of a US federal informant impersonating a Mexican drug cartel figure, have raised eyebrows among Iran specialists as to the seriousness of the plot.

The consensus view in US President Barack Obama’s administration is that Iran’s supreme leader, Ayatollah Ali Khamanei, probably knew of the alleged plot to kill the Saudi ambassador, while President Mahmoud Ahmadinejad did not.

Ahmadinejad has said Washington had fabricated the plot to cause a rift between Tehran and Saudi Arabia and dominate the Gulf. Iran's foreign minister has expressed disappointment at the European Union's apparent support for the US in its allegations that Iranian agents plotted the assassination of the Saudi ambassador to the US.

Ali Akbar Salehi was quoted Monday by Iran's official IRNA news agency as saying that Tehran did not expect the EU to go along with the American "game."

The EU on Friday ordered the assets of five people frozen in connection with the alleged plot in what it deemed a precautionary measure. Britain has also frozen the assets of plot suspects.

The Iranian government has denied any connection to the alleged plot, saying US officials have offered no proof.