Syrian anti-aircraft shot down an Israeli fighter jet on Saturday, as Israel struck Iranian facilities in Syria. Israel was responding after it had intercepted an Iranian drone in its territory. Anti-aircraft are weapons used to attack aircraft.

“IDF [Israeli Defence Forces] has targeted the Iranian control systems in Syria that sent the #UAV into Israeli airspace,” Jonathan Conricus, spokesperson of the IDF, said on Twitter. “Massive Syrian Anti-Air fire, one F16 crashed into Israel, pilots safe. Iran is responsible for this severe violation of Israeli sovereignty.”

The two pilots in Israel’s F-16 jet ejected and parachuted safely after the crash in Jezreel valley in northern Israel. The drone went down on Israeli territory and was in Israel’s possession, IDF spokesperson Brigadier General Ronen Manelis said, according to BBC.

Sirens were sounded in northern Israel following the Syrian fire. The Syrian state media reported that air defences opened fire in response to an Israeli act of “aggression”.

“This is a serious Iranian attack on Israeli territory,” The Guardian quoted Manelis as saying. “Iran is dragging the region into an adventure in which it doesn’t know how it will end. Whoever is responsible for this incident is the one who will pay the price.”

Russia and Iran, allies of Syria’s President Bashar al-Assad, began a military intervention in September 2015 to help the Syrian government regain territory from the Islamic State group. The civil war has claimed the lives of more than 3.4 lakh people and left huge swathes of Syrians as refugees.