The incident occurred as Russian-backed Syrian forces took part in operations against rebels on the edges of Golan Heights, a strategic plateau between Syria and Israel.
The Israeli Defense Forces (IDF) said it monitored the advance of the Syrian Sukhoi fighter jet and shot it down with a pair of Patriot missiles after it penetrated Israeli airspace by about 1.2 miles. It was not immediately clear where the plane crashed and no details were given as to the fate of the pilots.
"Since this morning, there has been an increase in the internal fighting in Syria and the Syrian Air Force's activity," the IDF said in a statement.
The Israeli military also said that it would "continue to operate against" any breach of a 1974 U.N. armistice deal that established buffer zones on the Golan. Russian-backed Syrian forces have been battling rebels and Islamic State militants at the frontier with Israel in recent weeks.
The incident comes hours after Israeli Prime Minister Benjamin Netanyahu met with Kremlin officials.
This is the second time Israel shot down a Russian-made Syrian jet. Four years ago, a Sukhoi-24 was shot down with Patriot missiles after entering Israeli airspace. The two Syrian pilots ejected from their aircraft and landed in Syrian territory.
Raytheon's Patriot missile system is designed to track and hunt fighter jets, helicopters, drones and low-flying cruise missiles. The U.S.-made surface-to-air defense system is used by 15 countries and has been deployed to war.