Federal officials say FBI and DEA agents have disrupted a plot to commit a “significant terrorist act in the United States” tied to Iran. ABC News first reported:

“The officials said the plot included the assassination of the Saudi Arabian ambassador to the United States, Adel Al-Jubeir, with a bomb and subsequent bomb attacks on the Saudi and Israeli embassies in Washington, D.C.

Bombings of the Saudi and Israeli embassies in Buenos Aires, Argentina, were also discussed, according to the U.S. officials.”

The case has been called “Operation Red Coalition” and traces back to an Iranian-American from Corpus Christi, Texas, who contacted a DEA informant in May, for help from a Mexican drug cartel to assassinate the Saudi ambassador. The Iranian-American thought he was dealing with a member of the Zetas Mexican drug organization, according to agents.

The assassination was allegedly “directed by elements of the Iranian government” according to CNN.

U.S. Attorney General Eric Holder confirmed the plot shortly before 2:15p.m. ET at a press event in Washington with FBI Director Robert Mueller and U.S. attorney in Manhattan Preet Bharara. Holder confirmed that 56-year-old Manssor Arbabsiar is accused of attempting to orchestrate a $1.5 million assassination plot of the Saudi Ambassador to the United States. Holder said Arbabsiar is in U.S. custody, and has confessed to the accusation.

You can watch his press conference, where he was joined by the FBI, below:

Arbabsiar, a naturalized U.S. citizen, expressed “utter disregard for collateral damage” in the planned bomb attacks in Washington, according to officials who spoke with ABC News.

Holder confirmed the plot was linked to the Iranian government, specifically the Quds force, and that the conspiracy “constitutes a flagrant violation of U.S. and international law.”

The Quds force is an elite unit of Iran’s Islamic Revolution Guards Corps (IRGC).

The Iranian government has denied the accusation, and say that the allegations are being used as a means for the United States to deflect attention from their own economic problems.

Holder said the U.S. would hold Iran accountable, and the foiling of the plot “marks a significant achievement.”

“Through the diligent and coordinated efforts of our law enforcement and intelligence agencies, we were able to disrupt this plot before anyone was harmed.  We will continue to investigate this matter vigorously and bring those who have violated any laws to justice.”

CNN reports on the criminal complaint filed Tuesday in the Southern District of New York against the alleged orchestrators of the attack, Manssor Arbabsiar, and Gholam Shakuri, an Iran-based member of Iran’s Quds Forces:

“Arbabsiar was arrested on Septemnber 29, 2011, at John F. Kennedy International Airport in New York. He will make his initial appearance on Tuesday before in federal court in Manhattan, the Justice Department said. He allegedly confessed to his participation in the murder plot, according to the Justice Department.

Shakuri remains at large.

The men are charged with the following crimes: conspiracy to murder a foreign official; conspiracy to engage in foreign travel and use of interstate and foreign commerce facilities in the commission of murder-for-hire; conspiracy to use a weapon of mass destruction (explosives); and conspiracy to commit an act of international terrorism transcending national boundaries.   Arbabsiar is further charged with an additional count of foreign travel and use of interstate and foreign commerce facilities in the commission of murder-for-hire.”

FBI Director Robert Mueller says many lives could have been lost in the plot to kill the ambassador with bombs in the U.S. ”We will not let other countries use our soil as their battleground,” Manhattan U.S. Attorney Bharara said at the press event.

President Barack Obama was first briefed on the plot in June, said White House spokesman Tommy Vietor.

Full transcript of Attorney General Eric Holder’s remarks.

This is a breaking story. The Blaze will update as more information comes to light.