"U.S. officials believe members of Hezbollah, the militant group backed by Iran, are smuggling advanced guided-missile systems into Lebanon from Syria piece by piece to evade a secretive Israeli air campaign designed to stop them," the Wall Street Journal reported.

"Some components of a powerful anti-ship missile system have already been moved to Lebanon within the past year, including supersonic Yakhont rockets, according to previously undisclosed intelligence."

Yet “to make it lethal, a system needs to be complete," said a senior defense official.

"Other systems that could target Israeli aircraft, ships and bases are being stored in expanded weapons depots under Hezbollah control in Syria, the Journal quoted current and former U.S. officials as saying."