Ominously, the officials said Israel appears to be preparing for open warfare with Iran and is seeking U.S. help and support.

"On the list of the potentials for most likely live hostility around the world, the battle between Israel and Iran in Syria is at the top of the list right now," said one senior U.S. official.

The US officials told NBC that Israeli F-15s hit Hama after Iran delivered weapons to a base that houses Iran's 47th Brigade, including surface-to-air missiles. In addition to killing two dozen troops, including officers, the strike wounded three dozen others. The report adds that the U.S. officials believe the shipments were intended for Iranian ground forces that would attack Israel.