Israel's military, which is dropping hints it was behind last week's airstrike on a Syrian chemical weapons facility, is said to be considering more raids, including targeting an Iranian electronic listening post in the disputed Golan Heights.

This is emerging amid reports that the United States had cleared Wednesday's airstrike against the Syrian facility, 5 miles from the border with Lebanon, and a convoy supposedly moving advanced Russian-built surface-to-air missiles to Lebanon for the Iranian-backed Hezbollah.

There have been unsubstantiated reports from U.S. sources the Israelis may have mounted two other airstrikes against Syrian targets that Damascus hasn't publicly acknowledged, as it has the attack on the military facility at Jamraya, 15 miles northwest of the Syrian capital.

The Jamraya attack, on which Syria has released a video of the damage caused by Wednesday's strike, was the first serious Israeli intervention in Syria since civil war broke out there March 15, 2011.

That underlined the Jewish state's growing unease that the bloodletting there will soon spill over into neighboring states like Jordan, Iraq, Lebanon and Turkey.

But the Israelis are likely most concerned that if the regime of Syrian President Bashar Assad is toppled, ending a brutal 43-year-old minority dynasty, it will be replaced with a more dangerous and unpredictable regime dominated by Sunni jihadists.

Syria has been one of Israel's most implacable foes since the creation of the Jewish state in 1948 and fought three wars against it.

Yet since Israel defeated Syria in the 1973 Middle East war, their northern border in the Golan, a strategic plateau captured from Syria in 1967, has been the country's quietest.

That's because Damascus understood that after Egypt, the Arab world's most populous nation, began a peace process with Israel in 1977, Syria didn't have the power to take on the Jewish state alone.

A successor regime of Islamist zealots may not show such pragmatic and self-imposed restraint.

And with Egypt now ruled by the Muslim Brotherhood since the February 2011 fall of President Hosni Mubarak, a staunch advocate of the 1979 peace treaty with Israel, there's a fear of an alliance of convenience between Cairo and a jihadist regime in Damascus.

Since Mubarak's fall, jihadists have been operating in growing strength in Egypt's Sinai Peninsula, which lies on Israel's southern border.

Israel's main fear is that the Syrian regime will transfer its sizeable arsenal of chemical weapons to Hezbollah, a key Lebanese ally which fought Israel to a standstill in a 2006 war.

The Israelis also want to ensure that Hezbollah, or the jihadists fighting the Damascus regime, don't get their hands on Syria's advanced conventional systems like Russia SA-17 surface-to-air missiles -- provided by Moscow after a 2007 Israeli airstrike that destroyed a half-built nuclear reactor on the Euphrates River -- and C-802 Chinese-designed anti-ship missiles. These would seriously challenge Israel's air and naval superiority in the region, dangerously exposing ground operations.

Israel, which hasn't officially acknowledged Wednesday's airstrike, may have been encouraged by the lack of retaliation by the Syrians, or the Iranians who are Assad's staunchest allies and are reportedly providing weapons and troops to help him stay in power.

Technically, Israel's still in a state of war with Syria. There's no benefit for Israel, faced with increasingly destabilized Arab neighbors, in widening that conflict but it can't allow Syria's arsenals to be seized by unpredictable enemies.

"The fact that ... Assad, who has been steadily losing his grip on the country in the face of a two-year rebellion, should dare defy repeated Israeli warnings about moving anti-aircraft missiles to Hezbollah ... is in itself alarming," observed Roula Khalaf of the Financial Times.

"So too is Israel's readiness to strike. There might be no immediate conflagration but the stakes have been raised much higher."

There are those who believe, contrary to the conventional wisdom in the region, that the Israelis would shed no tears if Assad were to be overthrown.

"He is a linchpin of the radical Iran-Hezbollah axis and a staunch rival of Israel," retired Israeli Brig. Gen. Michael Herzog noted in a Jan. 31 analysis for the Washington Institute for Near East Policy.

"His fall would therefore deal a major blow to Tehran, significantly weaken Hezbollah and dismantle the trilateral axis."