TEL AVIV, Israel - Israel shot down a Syrian fighter jet after it entered the country's airspace on Tuesday, an official said. “A Syrian aircraft infiltrated into Israeli airspace. The [Israeli Defense Forces] intercepted the aircraft in mid-flight, using the Patriot air defense system,” an IDF spokesman told NBC News, adding that the plane was thought to be a MiG. "The circumstances of the incident are being reviewed.” An unidentified Syrian military source described the shoot-down as an act of aggression, according to Syrian state TV.

The last time Israel downed a Syrian MiG was on Nov. 19, 1984, the IDF said. The Israeli policy is not to interfere in Syria's raging civil war, but officials have warned that anything that crosses the border will get shot down. A drone from Syria was shot down on Aug. 31 and shells from the fighting in Syria periodically land in the Golan Heights.

A Syrian fighter jet is seen in flames after it was hit by the Israeli military over the Golan Heights on Tuesday. JALAA MAREY / AFP - Getty Images

IN-DEPTH

- Paul Goldman

Reuters contributed to this report.