The United States says it has broken up an alleged Iranian plot to assassinate the Saudi ambassador to the United States in a bomb attack.

The U.S. Justice Department filed charges Tuesday against two Iranians for involvement in the plot, accusing them of conspiring with elements of the Iranian government to kill Saudi envoy Adel al-Jubeir.

Officials identified one suspect as Manssor Arbabsiar, a holder of Iranian and U.S. passports whom authorities arrested at New York's John F. Kennedy International Airport on September 29.

The officials named the second suspect as Gholam Shakuri, whom they described as an Iran-based member of the elite Iranian Quds Force. They said Shakuri remains at large.

U.S. Attorney General Eric Holder told a news conference Tuesday that the plot was “conceived, sponsored and directed” from Iran. He said Washington will hold the Iranian government accountable.

A White House spokesman said President Barack Obama was first briefed on the issue in June and directed his administration to provide all necessary support to the investigation. Mr. Obama praised the disruption of the alleged attack as a “significant achievement.”

Officials say Arbabsiar unknowingly hired an informant of the U.S. Drug Enforcement Administration to carry out the plot, believing the informant had ties to Mexican drug cartels capable of killing the Saudi ambassador. They say Arabsiar confessed to making a $100,000 downpayment on the scheme with a price tag of $1.5 million.