Israel has struck a suspected weapons convoy on the border of Syria and Lebanon, according to multiple sources.
Israeli jets carried out the strike overnight on the convoy which was said to be on its way into Syria, in the area of the Lebanon-Syria border.
Three squadrons of four jets carried out three separate sorties against the convoy, hitting it near the Lebanese village of Nabi Chit, about half way up the border with Syria in central Lebanon.
Early reports said the strike happened inside Lebanon, but Sky sources said the attack took place just inside Syria.
Sky News Middle East Correspondent Sam Kiley said: "We know from Sky sources that the Israelis have conducted an air strike involving three sorties by 12 planes - a very heavy airstrike, a high level of intent - on the village of Nabi Chit, near the bigger Syrian town of Zabadani. It's inside Syrian territory, therefore representing a possible strategic escalation.
"I'm told by security sources that were not directly involved that the most likely target were either shore to ship missles - very sophisticated missiles of the kind used by Hizbollah against an Israeli ship a few years ago off the coast of Lebanon - or sophisticated anti-aircraft missiles, both of which the Damascus regime have access to from Russia.
"They are recently understood to have taken substantial imports of these from Russia.
"Why are they such a worry to the Israelis? If Hizbollah were to get access to such anti shipping missiles and particularly to very sophisticated anti aircraft missiles, it would prevent the Israelis carrying out just the sort of airstrike that they've just done - it would shift the balance towards Hizbollah.
"Israel has always enjoyed air superiority in the region and it would lose it if these missiles were able to find the way into Hizbollah's hands.
"There is less of a suggestion that it was targeting chemical weapons."
Israel has in the last few months boosted isecurity and put a lot of tanks on its northern border with Syria, around the disputed Golan Heights. It has also installed its Iron Dome anti-missile missile system which has been used successfully to stop rockets coming out of Gaza.
An Israeli military spokeswoman declined to comment on the report.
Hizbollah also failed to comment.
In the run-up to the raid, Israeli officials had been warning very publicly of the threat posed to their country should high-tech anti-aircraft or anti-tank missiles reach Israel's enemies.
Lebanese militant group Hizbollah is a known enemy of Israel and has connections with Syria.
Israel fears sophisticated weaponery stockpiled by Bashar al-Assad's regime could fall into the hands of Hizbollah and could then be used to launch an attack against its citizens.
It was originally thought that Israel had waited until the convoy had crossed the border into Lebanon. A strike just inside Lebanon would had caused fewer diplomatic problems for Israel as it would avoid provoking Syria's ally Iran.
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