A leaked audio recording of Iranian foreign minister Mohammad Javad Zarif reveals that John Kerry revealed that information to Tehran, presumably during the negotiations for the deal with Iran over its nuclear-weapons development:
Former Secretary of State John Kerry informed him that Israel had attacked Iranian interests in Syria at least 200 times, to his astonishment, Mr. Zarif said. The context for this is Zarif’s attempt to explain the grip that the Revolutionary Guards have on the government in Tehran.
The “astonishment” comes from Zarif’s apparent ignorance of this fact while the Guards knew it all along, or at least that seems to be Zarif’s point.
The reference to “at least 200 times” is written somewhat ambiguously too; it could mean that Kerry told them one time about 200 Israeli operations, or told Zarif on 200 separate occasions, but it’s almost certainly a reference to one discussion.