FBI and DEA agents have disrupted a plot to commit a "significant terrorist act in the United States" tied to Iran, federal officials told ABC News today.

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.

U.S. Attorney General Eric Holder said in an announcement today that the plan was "conceived, sponsored and was directed from Iran" by a faction of the government and called it a "flagrant" violation of U.S. and international law.

"The U.S. is committed to holding Iran accountable for its actions," Holder said.