Strong signs Iran is supplying Syria with weapons, US says

A recent visit by the commander of Iran's elite Quds force to Damascus is the strongest sign yet that Iran is supplying weapons to aid Bashar Assad's crackdown on the Syrian people, a senior Obama administration official said Tuesday.

While the U.S. has long believed Iran is helping drive the deadly crackdown on dissent in Syria, the official says the visit by Quds Force Commander Ghassem Soleimani provides a concrete example of direct high-level cooperation between Iran and Syria.

The official spoke on condition of anonymity because this person was not authorized to speak publicly.

The administration's assertion comes amid heightened tensions between Washington and Tehran. Under the threat of increased U.S. sanctions, Iran has said it could block the strategic Strait of Hormuz; the Obama administration says it has warned Iran against taking such action.

Persian Iran has been Arab Syria's closest ally for decades, and the Islamic Republic has been a vocal supporter of Assad since the uprising against his regime began in March.

The revolt in Syria has turned increasingly militarized in recent months, with a growing risk of civil war. The U.N. says about 400 people have been killed in the past three weeks, on top of an earlier estimate of more than 5,000 dead over the past 10 months.

White House national security council spokesman Tommy Vietor said Iran's aid to Syria is a sign of Assad's "desperation."

"Assad is running out of money to continue financing his crackdown and has turned to Syria's only ally left," Vietor said. "No citizen in the world deserves to be repressed by its own government, and certainly not by Assad's lone friend."

The administration has called for Assad to step down, and say his regime's end is inevitable. Officials point to recent defections by senior Syrian military and government officials, including the decision by a member of parliament to leave Syria over the weekend, as signs that Assad's government is crumbling.