A month later, Iran sentenced an American-Iranian journalist to prison for spying. Tehran later rejected U.S. proposals for ending the international standoff over its nuclear energy program, which the United States believes is a cover for aspirations for nuclear weapons.
As Iran added inexorably to its stockpile of enriched uranium, the Republican Guard and Quds Force contributed to U.S. casualties in Iraq and Afghanistan, in part by supplying deadly new forms of explosives to insurgents in both countries, Western intelligence officials say.
“In addition to allegedly sponsoring this plot, Iran has supported and provided weapons for attacks on our soldiers in Iraq and Afghanistan,” said Sen. Saxby Chambliss (Ga.), ranking Republican on the Senate intelligence committee. “This has continued far too long with no repercussions.”
The alleged assassination plot would be the first known attempt by Iranians in decades to strike a foreign dignitary on U.S. soil. But Iran has long used proxy forces — most often the Lebanon-based militant group Hezbollah — to carry out targeted killings and terrorist strikes from the Middle East to Europe to South America.
Tehran also is increasingly engaged in tit-for-tat warfare with Western, Israeli and Arab intelligence operatives seeking to undercut Iran’s regional influence and cripple its nuclear program.
The most spectacular blows in the covert war in recent years have fallen on Iran. In the past four years, four Iranian scientists with links to the country’s nuclear program have been slain, by gunshot, bomb or poisoning, by unknown assailants. A fifth scientist barely escaped death in a car-bombing. Iran has accused the United States and Israel of killing the scientists as part of a larger program of sabotage and intimidation aimed at crippling the nuclear program. Neither the U.S. nor Israeli government has commented publicly on the slayings.
Iran’s nuclear program also was damaged by a computer worm that targeted enrichment operations. Some computer experts believe the worm, Stuxnet, was created by the Israelis, perhaps with U.S. help.
In interviews, Iranian officials complain of the damage inflicted by what they say is a black-operations program led by the United States and Israel, and some of them have threatened reprisals. At the same time, Iran faces increasing pressure from long-time rival Saudi Arabia and other Sunni Arab states that are intent on preventing Iran from becoming a nuclear power or expanding its regional influence.
Several Persian Gulf states joined the West in a campaign to isolate Iran’s chief Arab ally, Syrian President Bashar al-Assad. Iran has responded by sending oil, cash and arms to Assad, and by going on the offensive elsewhere. In August, Revolutionary Guard forces also started an intense campaign in the Kurdish border area in an attempt to destroy the Kurdish separatist organization PJAK, which officials in Tehran say is backed by the United States.
But while Iranian officials have acknowledged battling U.S. interests along an array of fronts, they scoffed openly at the new accusations, which a government spokesman on Tuesday dismissed as “big lies that will go nowhere.”
“These sorts of cliche behaviors are based on the old, hostile policies of America and the Zionists,” said Foreign Ministry spokesman Ramin Mehmanparast, “and are just foolish games.”
Staff writers Scott Wilson, Karen DeYoung and Greg Miller and researcher Julie Tate contributed to this report. Erdbrink reported from Tehran.