"This episode boils down to a warning by Israel to Syria and Hezbollah not to engage in the transfer of sensitive weapons," the source said. "Assad knows his survival depends on his military capabilities and he would not want those capabilities neutralised by Israel - so the message is this kind of transfer is simply not worth it, neither for him nor Hezbollah."
With official secrecy shrouding the event, few details were corroborated by multiple sources. All those with knowledge of the events - from several countries - spoke anonymously.
There was no comment from the Israeli government nor Hezbollah. Israel's ally the United States declined all comment. A Lebanese security source said its territory was not hit, though the army reported a heavy presence of Israeli jets through the night after days of unusually frequent incursions.
Such a strike or strikes would fit Israel's policy of pre-emptive covert and overt action to curb Hezbollah and does not necessarily indicate a major escalation of the war in Syria. It does, however, indicate how the erosion of the Assad family's rule after 42 years is seen by Israel as posing a threat.
Israel this week echoed concerns in the United States about Syrian chemical weapons, but its officials say a more immediate worry is that the civil war could see weapons that are capable of denting its massive superiority in airpower and tanks reaching Hezbollah; the group fought Israel in 2006 and remains a more pressing threat than its Syrian and Iranian sponsors.
Israeli officials have said they feared Assad may be losing his grip on some chemical weapons, including around Damascus, to rebel groups which are also potentially hostile to Israel. U.S. and European security sources told Reuters they were confident that chemical weapons were not in the convoy which was bombed.
Wednesday's action could have been a rapid response to an opportunity. But a stream of Israeli comment on Syria in recent days may have been intended to limit surprise in world capitals.