Syria's air defense forces shot down an Israeli war plane and four missiles on Thursday, Russia's RIA news agency said, citing a Syrian security source, but Israel's military said the report was bogus.
RIA later contradicted the report, saying that Syrian air defenses shot down several targets but did not shoot down an Israeli war plane. Damascus also retracted an earlier statement that it downed an Israeli fighter jet.
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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.
On Thursday night, the Syrian air force shot down a "hostile target" flying over the town of Kiswah, south of the capital Damascus, state media said. Saudi-owned TV station Al-Arabiya reported that Israeli planes attacked Iranian militia positions in the country's south.
State media quoted a military source but did not specify what the target was or where it came from. Syrian opposition sources on the ground said the area was close to where the Iranian-backed Lebanese Shi'ite group Hezbollah has a powerful presence with several bases.
The army added that reports that Israeli aircraft was hit are incorrect.
On Thursday, the Israel Defence Forces said in a statement on Twitter: "In the course of Syrian ground-to-air missile fire, (Israel's) air defences sighted a single trajectory toward an open area of the Golan Heights."
"At this stage it remains unclear whether there was indeed an impact in our territory. Our forces are scouring the area. Furthermore, the report about a strike on an Israeli aircraft or an Israeli aerial target are bogus," said the statement.
Earlier, Syrian state media said Syrian air defences shot down "hostile targets" flying over the town of Kiswah.
Israeli strikes on Syria "have been cut almost to zero" since a Russian plane was shot down near Latakia two months ago, a former head of Military Intelligence said earlier Thursday.
Maj. Gen. Amos Yadlin, interviewed on Radio 103, said Iran was "changing tactics" and has been reducing its presence in Syria in favor of Iraq and Lebanon.
"Apart from the Russians' anger with us, I assume they also passed stern messages to the Iranians," he said. "Russia's strategy is to stabilize Syria, and Iran was disrupting that by developing its precision missile facilities."
Yadlin, who now heads the National Institute for National Security Studies at Tel Aviv University, said a clash between Iran and Israel on Syrian territory wouldn't be beneficial to Russia, so a change in Iranian activity is already discernible in Syria.
The interception of the Russian aircraft caused a crisis between Israel and Russia. Since the incident, Prime Minister Benjamin Netanyahu has tried unsuccessfully to schedule meetings with Russian President Vladimir Putin, until the two met briefly in Paris some two weeks ago. Putin said recently that he had no further meetings planned with Netanyahu.
Haaretz reported in October that the Russians were taking a firmer line with Israel regarding the Israel Air Force's activity in the north. Among other things, the Russians demanded further clarifications from Israel about the IDF's activity in the north by means of a hotline established to prevent friction between the sides. In a few cases, radars in Russia's air defense systems were activated when the Israel Air Force operated in the north.