Israel is not getting involved in Syria's civil war, Defence Minister Moshe Yaalon said on Tuesday, while insisting the Jewish state would not permit the transfer of arms to Damascus ally Hezbollah in neighbouring Lebanon.
Yaalon was speaking just days after two Israeli air strikes near Damascus sent regional tensions soaring and as the United Nations protested about Israel warplanes overflying Lebanon.
The raids struck several military targets in the early hours of Friday and Sunday and may have been carried out by Israeli warplanes from Lebanese air space.
A senior Israeli source said they destroyed Iranian missiles en route to Hezbollah.
On Monday, an official in Damascus warned that "Syria will respond to the Israeli aggression and will choose the moment to do so."
"It might not be immediate because Israel now is on high alert," he added. "We will wait but we will answer."
Israel routinely refuses to relate to such reports, with Yaalon's remarks the first official comment, albeit indirect, on the strikes.
"We are not getting involved in the civil war in Syria but we have made clear what our interests are," he said on a tour of an area around the Gaza Strip in remarks broadcast on Israel's main radio stations.
"We have laid down red lines among which are the transfer of sophisticated weapons to terror organisations like Hezbollah and others, or (the transfer of) chemical weapons, or violations of our sovereignty along the border," he said.
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"In all these incidents, we will act to protect the security of the state of Israel."
In New York, UN spokesman Martin Nesirky called on Israel to halt increased military air patrols over Lebanon, which he called a "violation of Lebanese sovereignty," and said the UN Interim Force in Lebanon had protested after recording a surge in such flights.
On January 30, another strike on Syrian soil, which was attributed to Israel, destroyed what military intelligence officials say was a shipment of Russian-made SA-17 anti-aircraft missiles destined for Hezbollah.
Yaalon also referred to three instances of Syrian fire on the Golan Heights over the past 24 hours, which the military believes was unintentional fallout from the intense fighting on the Syrian side of the strategic plateau.
"The forces in the area are in place, and the moment there is fire from the Syrian side -- they don't need authorisation from me or from the chief of staff or from the regional commander -- when they identify the source of fire, they will destroy it," he said.
In the Gaza Strip, the premier of the ruling Palestinian Islamist movement Hamas, Ismail Haniya, denounced Israel's"aggression against Syria." He said this was a "grave interference" requiring "appropriate actions" from Arab and Muslim states.
"We completely reject all Zionist aggression against Syria or any other Arab and Islamic country whatever the excuses of the occupier (Israel) to justify its crimes," he added in a statement.
Police wielding batons broke up a demonstration organised by the Popular Front for the Liberation of Palestine to protest the Israeli air strikes.
PFLP official Nasrallah Jarhun said three people were injured.