If a shadowy Iranian government unit indeed plotted to kill Saudi Arabia's U.S. ambassador, it would be an unprecedented -- and worrying -- spread of Iranian covert activities into the United States, experts and officials said.
It could also reflect a growing struggle for political and security powers within Iran, they said.
U.S. and European officials said while there were cases in the 1980s and 1990s in which Iranian government agents were linked to attacks in the West -- often against Iranian dissidents -- such activity dropped off after crackdowns by Western security agencies.
On Tuesday, FBI director Robert Mueller and Attorney General Eric Holder announced that two men of Iranian extraction had been charged in U.S. federal court with participating in a purported assassination plot against Saudi Ambassador Adel al Jubeir which allegedly was "directed" by elements of the Iranian government.
Authorities linked one of the defendants, Gholam Shakuri, who is at large and believed to be in Iran, to the Quds Force, a secretive unit of Iran's Islamic Revolutionary Guard Corps (IRGC). The Quds Force is allegedly responsible for providing IRGC liaison and support for what the Justice Department described as "terrorist activities abroad."
A plot against targets inside the U.S. "would be a first for the Quds Force," said Kenneth Pollack, a former CIA and National Security Council analyst who now heads the Saban Center at the Brookings Institution in Washington.
"I do want to hear more about what evidence (U.S. authorities) have and why they believe" that the Quds Force was involved in the plot against the Saudi envoy, Pollack said. But he added that "there is always a first time".
U.S. officials say that the Quds Force and IRGC have historically been close to Hizbollah, the Shi'ite movement and militia which plays a major role in Lebanon and has warred with Israel. U.S. officials also have said that in the years following the U.S. invasion which deposed Iraqi dictator Saddam Hussein, the Quds Force played a major role in supporting insurgents who attacked and killed U.S. troops trying to pacify the country.
A secret unit of the Quds Force known as "Department 9000" acted as a liaison between Shi'ite insurgents in Iraq and the IRGC, U.S. officials said at the time, though at some point it also began to aid anti-American Sunni insurgents.
In 2007 General David Petraeus, who recently became director of the CIA, told Congress the Quds Force was working with a secret arm of Hizbollah known as "Department 2800" to train, arm, finance and in some cases direct Shi'ite militia units in Iraq and turn them into a Hizbollah-like movement opposing U.S. forces and the Iraqi government.
U.S. and European officials have said that, through units like the Quds Force, Iran continues to cause trouble for U.S. forces in neighboring countries like Iraq and Afghanistan.
PLOT IN WEST A FIRST FOR QUDS FORCE
But several U.S. and European officials and experts said they were unaware of evidence in recent years linking the Quds Force or IRGC to plots targeting Europe or the United States.
A person familiar with U.S. government assessments of Iran said President Barack Obama's administration was increasingly concerned that power centers in Iran were competing against each other, breaking down centralized control over government units including the IRGC -- Iran's main security force.
Of particular concern, the source said, was evidence suggesting that the IRGC was operating autonomously of other governmental elements.
Pollack said that in a 1992 case, in which three Iranian-Kurdish opposition leaders and their translator were killed in an attack a restaurant in Berlin, German authorities alleged that the assassination had been ordered by Ayatollah Ali Khamenei, then as now Iran's Supreme religious leader. The Iranian government was also linked to the deadly 1994 bombing of a Jewish center in Buenos Aires which killed 85 people.
But Pollack said there were indications that the IRGC may have been acting on its own, without Khamenei's sanction, when its units detained five British sailors on a racing yacht in the Persian Gulf in 2009, sparking an international incident.
In 1980, an American militant who converted to Islam and worked at an Iranian government office in Washington following the revolution which deposed Shah Reza Pahlavi shot dead a critic of Ayatollah Khomeini, Iran's revolutionary leader, at the dissident's home in suburban Washington D.C.
The militant, Daoud Salahuddin, then fled to Iran, from where U.S. law enforcement officials spent several years unsuccessfully trying to lure him back to the United States to face justice.
Pollack and U.S. officials said that what was alarming about the latest arrests was the allegation that Iranian authorities, or some faction among them, had now embarked on a violent attack well outside the recognized operational boundaries of the IRGC and Quds Force.
(Editing by Cynthia Osterman)
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