The Israel Defense Forces confirmed that two Patriot missiles were fired at the Syrian Sukhoi fighter jet.

The Defence Forces said the fighter jet infiltrated about one mile into Israeli airspace.

The IDF tweeted: "Two Patriot missiles were launched at a Syrian Sukhoi fighter jet that infiltrated about 1 mile into Israeli airspace. The IDF monitored the fighter jet, which was then intercepted by the Patriot missiles."

In another post, it said: "Sirens sounded in the Golan and Emek HaYarden regional councils and the city of Katzrin. More details to follow."

The forces said there has been an increase in the internal fighting in Syria and the Syrian Air Force's activity since Tuesday morning.

"Since this morning, there has been an increase in the internal fighting in Syria and the Syrian Air Force's activity. The IDF is in high alert and will continue to operate against the violation of the 1974 Separation of Forces Agreement," IDF tweeted.

UN Photo/Wolfgang Grebien