The Israeli military has attacked targets deep in Syria in an attempt to curb the threat posed by Iranian-backed forces on its border, after one of its warplanes was brought down by anti-aircraft fire from inside the war-torn country.

The Israeli Defence Force said the F-16 came down amid heavy anti-aircraft fire after it attacked an Iranian facility deep in Syria that had been used to control a drone that had entered Israeli airspace on Saturday morning. It said the two pilots ejected before the crash. One is in a serious condition.

It responded by launching a “large-scale attack” on the T4 military base near Palmyra, a major escalation in its efforts to keep Iranian-backed Hizbollah military infrastructure far from its border. The IDF said it had hit 12 military targets in Syria, four of which it said were primarily Iranian.