The Israeli military shot down a Syrian fighter jet after it entered Israeli airspace on Tuesday afternoon, the Israel Defense Forces (IDF) said, raising fears of further military escalation in the region.

The Russian-made Sukhoi jet entered two kilometers into Israeli airspace when two Patriot missiles were launched to intercept the aircraft, the IDF said. The missiles hit the jet once it had crossed back into Syrian airspace, the IDF said, adding that the military did not know what happened to the pilot of the aircraft.

Syria said its jet was conducting an operation against "terrorist groups" when it was hit by Israeli fire, according to a state media report.

"The Israeli enemy targeted one of our warplanes while conducting air raids against these groups in the area of Saida on the outskirts of al-Yarmouk Basin in the Syrian airspace," a Syrian state TV banner said, quoting a military source.

Yarmouk basin is one of the last remaining areas in southern Syria not yet under government control. Syrian forces, backed by the Russian military, have been carrying out an extensive campaign in the area in recent days, attempting to wrest control from an ISIS affiliate that is clinging on to a small pocket of territory.

Israel said there had been a notable increase in activity by the Syrian military in the area on Tuesday, especially the Syrian air force, as a result of ongoing internal fighting in the war-torn country.

The jet took off from the T-4 military base northeast of Damascus, according to IDF spokesman Lt. Col. Jonathan Conricus. Israel has struck the T-4 base multiple times in the last year, targeting what the Israeli military has said are Iranian military assets at the base.

Before it launched its strike, Israel communicated with Russia to make sure the jet was Syrian, and not part of the Russian air force, according to Conricus. So-called "deconfliction measures" have been in place between the two countries since Russian forces entered Syria on behalf of President Bashar al-Assad.

The jet was either a Sukhoi 22 or Sukhoi 24, the IDF said Tuesday. Both jets are Russian-made aircraft developed in the 1960s and 1970s and operated by the Syrian air force.

One day earlier, Israel launched two missiles from the David's Sling missile defense system at two Syrian rockets which the IDF believed were heading for Israeli territory. When it became clear the two Syrian SS-22 missiles were going to land inside Syria, the David's Sling missiles were ordered to self-destruct, the Israeli military said. One missile successfully self-destructed, while it was unclear what happened to the second, the military said.

It marked the first time David's Sling has been used operationally. Designed to intercept medium and long-range missiles, David's Sling is a larger, more powerful version of Iron Dome.

Israel last shot down a Syrian fighter jet in September 2014 under similar circumstances. The IDF said that jet -- a Sukhoi 24 -- had entered one kilometer into Israeli airspace before it was downed by a single Patriot missile. The pilot and co-pilot ejected and landed in Syria.

In February, Syria shot down an Israeli F-16 fighter jet which came under "massive anti-aircraft fire," the IDF said at the time. The incident happened after an Iranian drone penetrated Israeli airspace, prompting Israeli airstrikes against Syria during which the fighter jet was downed.

Both pilots aboard the Israeli jet ejected. One pilot was severely injured during the ejection, while the second was lightly wounded. (CNN)

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