Israel's air force operated in Lebanon's south on Monday, according a Syrian source quoted on the Al-Masdar News website. Israeli planes have recently been operating along the Lebanese-Syrian border after "stalking this region several times last week," the report claimed.

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The report cited a source saying that even though Israeli planes did not enter Syria's airspace, the Syrian military still raised alert levels and prepared air defense systems for a potential attack.

The reason for the high alert in Syria, the report said, is that the Israeli Air Force usually uses this route to launch attacks in the Damascus and Homs provinces.

Haaretz reported earlier this week that Israel is increasingly worried by the Iranian-Hezbollah effort to set up production lines for precision weaponry in Lebanon. Some of the necessary materials are now being smuggled on the frequent flights from Tehran to Beirut, rather than overland through Syria.

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Furthermor, Israeli decision-makers are worried about developments in Lebanon, including Russia’s growing interest in events there and the return of some Hezbollah fighters from Syria. Israel has already announced that it intends to continue building a barrier along the border despite Lebanese warnings.

Monday's report came after the Syrian Observatory for Human Rights, which monitors the war in Syria, said Israel carried out a missile attack south of Damascus last Thursday evening.

Israel has not said whether it conducted the attack and Syrian state media did not identify who carried it out.

Russia's RIA news agency said, citing a Syrian security source, that Syria's air defense forces shot down an Israeli war plane and four missiles, but Israel's military said the report was bogus.

On Friday, the Israeli army said it found fragments which most likely belonged to a Syrian anti-aircraft missile in an open field in the Golan Heights.