Israeli aircraft carried out several strikes on Syria overnight, prompting the launch of ground-to-air missiles in response, one of which was intercepted, the army said on Friday.
The regime army said on Friday that four Israeli warplanes struck a military target "on the way to Palmyra," the famed desert city it recaptured from Daesh terrorists earlier this month.
Israeli warplanes "penetrated our air space at 2:40 am (0040 GMT) via Lebanese territory and hit a military target on the way to Palmyra," it said in a statement carried by news agency SANA.
Meanwhile, the Israeli army said that all of its aircrafts were unharmed in the overnight operation over Syria.
It was the most serious incident between the two countries, which remain technically at war, since civil war broke out in Syria in March 2011.
"Several anti-aircraft missiles were launched from Syria following the mission and (army) aerial defense systems intercepted one of the missiles," an Israeli army statement said.
Both Israeli and foreign media have reported Israeli air strikes inside Syria targeting arms convoys of Lebanese militant group Hezbollah, which fought a devastating 2006 war with Israel and is now fighting alongside the Assad regime.
But normally Israel makes no official comment.
The missile fire prompted air raid sirens to go off in the Jordan Valley during the night, the Israeli army said.
Israeli Channel 10 TV reported that Israel deployed its Arrow defense system for the first time against a real threat and hit an incoming missile intercepting it before it exploded in Israel.
It also showed footage from Jordan of what was described as remnants of the missile.
It was not immediately clear how debris from the missile may have ended up in neighboring Jordan.
Other Israeli media also reported that the Arrow was deployed. The Haaretz daily said the interception took place north of Jerusalem.
However, the Arrow is designed to intercept missiles in the stratosphere so it remained unclear why the system would have been used in this particular incident.