Israeli army reservists were surprised on Sunday to receive orders to immediately leave their jobs and families and report to the northern border with Syria.
The massive ground forces exercise follows a large Air Force drill conducted over the past week.
Both are seen as a clear message to Iranian forces just over the border in Syria to not further test the Jewish state.
Army officials, however, denied that Sunday's surprise call-up was directly tied to escalating tensions with Iran.
The IDF explained that the drill had been planned for some time, but that it was kept secret, even from the participating units, to test their response to an emergency call-up in the event of an actual outbreak of war.