Brussels, Belgium ? Two Iranians detained by U.S. forces in Iraq were senior members of Iran’s elite Revolutionary Guards and had coordinated attacks against coalition troops and Iraqi civilians, the head of an Iranian opposition group said Thursday.

The White House said earlier this week that U.S. troops had caught a group of Iranians in a raid on suspected insurgents in Iraq. Two of the men had diplomatic immunity and were released to Iran, but the other two were kept in custody.

Maryam Rajavi, who heads the National Council of Resistance of Iran, an anti-regime umbrella group based in Paris, said the two men being held were senior members of the Iranian Revolutionary Guards’ Qods force and were responsible for sectarian attacks in Iraq.

She cited the group’s intelligence officials as the source of the information.

It was not possible to independently verify Rajavi’s claim, but the group has provided relatively accurate information on developments in Iran over the past several years, including details on the country’s secretive nuclear program.

In Washington, a Pentagon official said Thursday that U.S. forces had found “indications and evidence that all of the people rounded up, including the two Iranians, are involved in the transfer of IED technologies from Iran to Iraq.” IED stands for improvised explosive devices.

The U.S. military has confirmed that troops found documents, but it was not clear if any actual explosives were found.