Middle East unrest increases the chance of Israel becoming embroiled in a surprise war, the head of its air force said on Wednesday.
"When you look (around) today I think that a surprise war can be born in very many configurations," Major General Amir Eshel told a conference near Tel Aviv in remarks broadcast on local television and radio.
"I don't so much see a surprise war in the near term, but it can be born from isolated incidents which escalate very quickly and oblige us to act across the spectrum," he said, without elaborating.
He said that the fall to rebel forces of Syrian President Bashar al-Assad, with his large stock of missiles, could precipitate conflict.
"If Syria collapses tomorrow, we are liable to find ourselves in this stew very quickly and in a very big way," he said.
"The enormous arsenal parked there... will be spread all over the place and you find yourself having to act on a very broad scale."
He said that Syria's order from Russia of advanced S-300 air defence weapons was just the latest in a long line of missile purchases.
"From the small budget that Assad has, he has spent billions in the past few years to buy the best systems that the Russians can produce -- the SA 22, SA 17, SA 24, the S-300 which is on it's way," he said.
Earlier, a defence official sounded a more upbeat note, saying that Israel's ability to deter attack on its positions in the occupied Golan Heights remains undiminished despite an uptick in fire from the Syrian side of the ceasefire line.
"The good news is that the continued stability of the Golan Heights (and) the deterrent power of the Israeli army have not been weakened," senior defence adviser Amos Gilad told army radio.
"Daily life goes on as usual," he said, in what appeared to be an attempt to calm nerves after two days of fire and counter-fire on Israel's northeast flank.
Israeli chief of staff Lieutenant General Benny Gantz issued a personal warning to President Bashar al-Assad on Tuesday after Syrian troops fired across the armistice line on the Golan, hitting an Israeli military vehicle.
The strategic plateau has been tense since the beginning of the conflict in Syria more than two years ago.
Israel, which is technically at war with Syria, seized 1,200 square kilometres (460 square miles) of the Golan from its Arab neighbour in the 1967 Six-Day War.
It annexed the territory in 1981 in a move never recognised by the international community.