WASHINGTON (Reuters) -- U.S. President George W. Bush has authorized the U.S. military to kill or capture what he claimed Iranian agents active inside Iraq, The Washington Post reported on Friday, citing government and counterterrorism officials with direct knowledge of the plan.

The move, approved last fall, is aimed at weakening Iran's influence in the region and forcing Tehran to abandon its nuclear program, citing the unidentified officials.

For more than a year, U.S. forces have held dozens of Iranians for a few days, taking DNA samples from some as well as photographs and fingerprints from all those captured, the report said.

Several Iranian officials have been detained in three U.S. raids over the last month.