Foreign Relations

"He gave no figures for the number of people who are crossing but said the number has fallen since Kurdish security forces boosted border security in the past few months."

"We are not just talking about Iranians passively dealing with al-Qaida," one former U.S. official who worked in Iraq said, speaking on condition of anonymity. "We are talking about al-Qaida at Revolutionary Guard bases and safe houses. This is active assistance."

The Revolutionary Guards are the shock troops of Iran's Islamic revolution, a well-funded force of 200,000 that answers to the country's Islamic leaders and not the military.