American prosecutors charged two Iranians on Tuesday for plotting to assassinate the Saudi ambassador to the U.S. using a hit squad from Mexico's drug cartel.

In the criminal complaint unsealed in New York, charged were leveled against naturalized U.S. citizen Manssor Arbabsiar, 56, and Gholam Shakuri, who has links to Iran's Qud Force, a special-operations unit of the Iranian Islamic Revolutionary Guard Corps.

Arbabsiar was arrested at the John F. Kennedy Airport in New York on Sept. 29 before he could fly to Mexico to finalize payment for the Mexican hit squad, according to the U.S. Justice Department. He is detained without bail. Shakuri is still at large.

U.S. Attorney General Eric Holder said the two have co-conspirators in Iran. The Iranian mission to the United Nations in New York denied the plot while the Saudi embassy in Washington issued a statement condemning the alleged plot to kill Ambassador Adel A. Al-Jubeir.

The assassination plot was discovered in January after Arbabsiar approached a Drug Enforcement Administration agent posing as a member of the violent Zetas drug cartel and offered $1.5 million to kill Al-Jubeir.

Arbabsiar then held multiple meetings with U.S. agents posing as Zetas members and wired $100,000 as down payment to a U.S. government account in New York. When he was arrested, he confessed to the plot and agreed to cooperate with U.S. authorities.