The IDF isn't saying anything publicly, but US and other western intelligence agencies are convinced that a series of overflights of Lebanon on Thursday and Friday targeted a convoy of advanced missiles that were being transferred to the Lebanese terrorist group Hezb'allah.

NBC News:

Israeli warplanes launched airstrikes against targets inside Syria on Friday, U.S. officials told NBC News.

It's believed the primary target was a shipment of weapons headed for Hezbollah in Lebanon, they said. A senior U.S. official said the airstrikes were believed to be related to delivery systems for chemical weapons.

An Israeli spokesman in Washington said that Israel would not comment specifically on the reports but said that "Israel is determined to prevent the transfer of chemical weapons or other game-changing weaponry by the Syrian regime to terrorists, especially to Hezbollah in Lebanon."

It wasn't clear whether the Israelis alerted the U.S. before the attack. White House officials referred all questions to the Israelis.

But Qassim Saadedine, a commander and spokesman for the rebel Free Syrian Army, told the news agency: "Our information indicates there was an Israeli strike on a convoy that was transferring missiles to Hezbollah. We have still not confirmed the location."

Rebel units were in disagreement about what type of weapons were in the convoy, Reuters reported. A rebel from an information-gathering unit in Damascus that calls itself "The Syrian Islamic Masts Intelligence" said the convoy carried anti-aircraft missiles.

The rebel, who asked not to be named, added: "There were three strikes by Israeli F-16 jets that damaged a convoy carrying anti-aircraft missiles heading to the Shi'ite Lebanese party (Hezbollah) along the Damascus-Beirut military road. "One strike hit a site near the (Syrian) Fourth Armoured Division in al-Saboura but we have been unable to determine what is in that location".

However Saadedine told Reuters he did not think the weapons were anti-aircraft. "We have nothing confirmed yet but we are assuming that it is some type of long-range missile that would be capable of carrying chemical materials," he said.

Things are getting dicier for Israel. Hezb'allah spiritual leader Hassan Nasrallah said this week that "Syria's friends" will not let Assad fall. The Lebanese English language paper Daily Star says that Nasrallah hinted that not only Hezb'allah would intervene militarily, but also Iran and Russia if worse comes to worse.

"Syria has real friends in the region and the world that will not let Syria fall in the hands of America, Israel or Takfiri groups. They will not let this happen," Nasrallah, Assad's closest ally in Lebanon, said in a televised speech.

"How will this happen? Details will come later. I say this based on information...rather than wishful thinking," Nasrallah added.

If the Israeli defense forces intercepted a shipment of long range missiles capable of carrying chemical weapons bound for Hezb'allah, they must think things are going to heat up in the near future. Hezb'allah is already heavily engaged in helping their patron President Assad and Nasrallah's guarantee to the Syrian regime is a clear signal that Syria's "friends" may be willing to fight to see Assad remain in power.

No need to explain what an Iranian and/or Russian intervention in Syria would mean.