U.S. forces tracking Iranians in Iraq

AP: "We've got about 50 of those," he said, referring to the Iranian forces. "They go back and forth. There's a porous border."

The military has stepped up allegations against Iran in recent weeks, saying it supplies militants with arms and training to attack U.S. forces.

Iran denies the allegations and says it supports efforts to stop the violence.

"We know they're here and we target them as well," he said, citing intelligence reports as evidence of their presence...more