The operations described by Hersh involve support for Baluchi and Arab separatist groups in Iran, "seizing members of al-Quds, the commando arm of the Iranian Revolutionary Guard, and taking them to Iraq for interrogation, and the pursuit of 'high-value targets' in the president's war on terror, who may be captured or killed".
There have been reports from Iran of assassinations of military officers, which Tehran has sometimes blamed on US and British operations. Both the US and Britain insist they are focused on diplomatic means to convince the Iranian government to suspend uranium enrichment and reprocessing.
Earlier this month an international delegation to Tehran delivered a package of economic and diplomatic incentives for the government to comply with UN security council demands. Yesterday, the Iranian foreign minister, Manouchehr Mottaki, said the package was being studied "carefully and strongly".
Iran insists its nuclear programme is purely peaceful, while western governments believe it is being used as a front for developing weapons, despite a US intelligence estimate published late last year concluding that Iran had closed down its weaponisation programme in 2003. The EU has intensified its travel and financial sanctions on Iran, while the Bush administration has said it will press for more punitive measures in the security council.
There has been persistent speculation that the Bush White House is considering air strikes against Iranian nuclear facilities before it leaves office next January.
Over the weekend, the commander of Iran's Revolutionary Guards, Major General Mohammad Ali Jafari, told a Tehran newspaper that Iran would retaliate against any US or Israeli attack on its nuclear installations by targeting the global oil supply.