Syria and Iran have threatened to retaliate for an Israeli air raid near the capital Damascus.
Syrian ambassador to Lebanon Ali Abdul-Karim Ali says Damascus has "the option and the surprise to retaliate." He said he cannot predict when the retaliation will be, saying it is up to relevant authorities to prepare for it.
In Iran, the semi-official Fars news agency quoted deputy foreign minister Hossein Amir Abdollahian on Thursday as saying the raid on Syria will have significant implications for the Israeli city of Tel Aviv.
US officials said Israel launched a rare air strike inside Syria on Wednesday, targeting a convoy believed to contain anti-aircraft weapons bound for Hizbollah.
The Syrian military denied the existence of any such shipment and said Israel targeted a scientific research facility outside Damascus.
Russia had earlier said it was 'deeply concerned' over reports that Israeli jets attacked a scientific research centre inside Syria. The country held back from condemning the action as yet, but said it would do so if the report was true.
Syria announced on Wednesday that an Israeli air strike attacked the research centre after reports had emerged out of Israel earlier claiming a convoy had been attacked on the Syria-Lebanon border.
Syrian officials claimed Israeli jets had entered their airspace at low altitude, under the radar, and hit the facility in Jamraya, near Damascus, killing two site workers.
State television quoted the military as saying: "They ... carried out an act of aggression, bombarding the site, causing large-scale material damage and destroying the building."
Earlier reports had claimed that Israeli jets had hit a convoy allegedly carrying weapons to Lebanon's Hizbollah movement. According to Sky sources, the attack took place just inside Syria.
Sky's Middle East correspondent Sam Kiley said on Wednesday: "We know from Sky sources that the Israelis have conducted an air strike involving three sorties by 12 planes - a very heavy air strike, a high level of intent - on the village of Nabi Chit, near the bigger Syrian town of Zabadani.
He said it was possible that the Israelis had been targeting a suspected shipment of ship-to-shore and anti-aircraft missiles.
Israeli officials were concerned that if the anti-aircraft missiles fell into the hands of Lebanese militant group Hizbollah, Israel could lose the air superiority it had enjoyed until now.
It was not immediately clear whether both the Sky sources and the Syrian media were referring to the same air strike, but the Syrian army denied that an Israeli air strike had targeted a weapons convoy on the border.
There was no official comment from Israel on the statements from Iran, Syria or Russia.
Tzahi HaNegbi, an MP close to Prime Minister Benjamin Netanyahu, commented generally, saying: "The best thing that Israel has been hoping for for a long time is that the West will take control of these weapons.
"But the world is not ready to take such a decision as it did in Libya or Iraq, so Israel finds itself facing a dilemma which we alone can resolve."
Iran had previously warned that any attack on Syria would be seen as an attack on Iran.