With Israel's usually talkative government maintaining an uncharacteristic silence, information on the mysterious incident has come almost exclusively from abroad.
Discussing the incident on an Israeli TV station Sunday, an outspoken former U.S. ambassador to the U.N. said he thought Israel might have been attacking a nuclear installation, "a message not only to Syria, but to Iran."
Tzachi Hanegbi, chairman of the Israeli parliament's foreign affairs and defense committee, told reporters he instructed military intelligence chief Amos Yadlin to avoid any mention of Syria at a committee meeting on Sunday. Panel members regularly report to journalists during and after committee meetings.
In a statement some participants took to be an oblique reference to the success of the alleged Syria raid, Yadlin told the meeting, "Israel's deterrence has been rehabilitated since the Lebanon war, and it affects the entire regional system, including Iran and Syria," according to a lawmaker who was present. Yadlin was referring to the inconclusive results of Israel's campaign against Hezbollah in Lebanon last summer.
The lawmaker spoke on condition of anonymity because he was not authorized to disclose the meeting's contents to the media.
Foreign news reports have suggested that Israel struck a Syrian site designed to make non-conventional weapons, possibly a nuclear installation built with North Korean help..
"I think it would be unusual for Israel to conduct a military operation inside Syria other than for a very high value target, and certainly a Syrian effort in the nuclear weapons area would qualify," the former U.N. ambassador, John Bolton, told Israeli Channel 10 TV in an interview broadcast Sunday.
"I think this is a clear message not only to Syria, I think it's a clear message to Iran as well, that its continued efforts to acquire nuclear weapons are not going to go unanswered," Bolton said.
CBS News correspondent Robert Berger reports that if Bolton's assessment turns out to be true, then Israel risked going to war to send a clear message - that nuclear weapons in Syria will not be tolerated.
In other developments:
Bolton, who has long called for a hard line against the Syrian and Iranian regimes, did not indicate that he had first-hand information about the incident.
Other hypotheses have posited that Israel was on an intelligence-gathering mission, testing Syria's air defenses, scouting an air corridor for a future strike against Iranian nuclear facilities, or hitting a shipment of arms destined for the Lebanese guerrilla group Hezbollah, a close ally of both Syria and Iran.
In the past, Israel often has been swift to announce such operations. This time, Syria cryptically announced the incident, announcing its air space had been entered and that Israel had "dropped munitions." Syria has offered no evidence of any Israeli attack.
Syria and Israel fought each other during both the 1967 and 1973 Mideast wars. Their last direct military confrontation was in neighboring Lebanon in 1982, when Israel's air force shot down dozens of Syrian warplanes and Israel destroyed Syrian tanks.
Israel has dismissed recent calls by Syria to restart peace talks, citing the Damascus regime's continued support for Palestinian militant groups and Hezbollah guerrillas in Lebanon.