You're reading: US defense chief warns Iran on nuclear program

WASHINGTON, March 6 (Reuters) - U.S. Defense Secretary Leon Panetta on March 6 vowed the United Stations would take military action to prevent Iran from acquiring a nuclear weapon if diplomacy fails.

"Military action is the last alternative when all else fails," he said in prepared remarks to the pro-Israel lobbying group AIPAC. "But make no mistake, we will act if we have to."