The United States believes Israel has conducted an airstrike into Syria , two U.S. officials first told CNN . U.S. and Western intelligence agencies are reviewing classified data showing Israel most likely conducted a strike in the Thursday-Friday time frame , according to both officials . This is the same time frame that the U.S. collected additional data showing Israel was flying a high number of warplanes over Lebanon . One official said the United States had limited information so far and could not yet confirm those are the specific warplanes that conducted a strike . Based on initial indications , the U.S. does not believe Israeli warplanes entered Syrian airspace to conduct the strikes . Both officials said there is no reason to believe Israel struck at a chemical weapons storage facilities . The Israelis have long said they would strike at any targets that prove to be the transfer of any kinds of weapons to Hezbollah or other terrorist groups , as well as at any effort to smuggle Syrian weapons into Lebanon that could threaten Israel . The Lebanese army website listed 16 flights by Israeli warplanes penetrating Lebanon 's airspace from Thursday evening through Friday afternoon local time . The Israeli military had no comment . But a source in the Israeli defense establishment told CNN 's Sara Sidner , `` We will do whatever is necessary to stop the transfer of weapons from Syria to terrorist organizations . We have done it in the past and we will do it if necessary the future . ''
Sources say a strike mostly likely occurred in the Thursday-Friday time frame . The U.S. does not believe Israeli warplanes entered Syrian airspace .