Syria’s ambassador to Lebanon declared that Syria had “the option and the capacity to surprise in retaliation.” The Iranian deputy foreign minister warned that the attack would have “grave consequences for Tel Aviv,” while the Russian Foreign Ministry said the strike “blatantly violates the United Nations Charter and is unacceptable and unjustified, whatever its motives.” Lebanon’s Foreign Ministry also condemned the attack — as did some Syrian rebels, seeking to deny President Bashar al-Assad of Syria a chance to rally support as a victim of Israel.

Many questions swirled about the target, motivations and repercussions of the Israeli attack, which Arab and Israeli analysts said demonstrated the rapid changes in the region’s strategic picture as Mr. Assad’s government weakens — including the possibility that Hezbollah, Syria or both were moving arms to Lebanon, believing they would be more secure there than with Syria’s beleaguered military, which faces intense attacks by rebels on major weapons installations.

American officials said Israel hit a convoy before dawn on Wednesday that was ferrying sophisticated SA-17 antiaircraft missiles to Lebanon. The Syrians and their allies said the target was a research facility in the Damascus suburb of Jamraya.

It remained unclear Thursday whether there was one strike or two. Also unclear was the research outpost’s possible role in weapons production or storage for Syria or Hezbollah, the militant Lebanese Shiite organization that has long battled with Israel and plays a leading role in the Lebanese government.

The Jamraya facility, several miles west of Damascus, produces both conventional and chemical weapons, said Maj. Gen. Adnan Salo, a former head of the chemical weapons unit in the Syrian Army who defected and is now in Turkey.

Hezbollah indirectly confirmed its military function in condemning the attack on Arab and Muslim “military and technological capabilities.” That raised the possibility that Israel targeted weapons manufacturing or development, in an attack reminiscent of its 2007 assault on a Syrian nuclear reactor, a strike Israeli never acknowledged.

But military analysts said that the Israeli jets’ flight pattern strongly suggested a moving target, possibly a convoy near the center, and that the Syrian government might have claimed the center was a target to garner sympathy. Hitting a convoy made more sense, they said, particularly if Israel believed that Hezbollah stood to acquire “game-changing” arms, including antiaircraft weapons. Israeli leaders declared days before the strike that any transfer of Syria’s extensive cache of sophisticated conventional or chemical weapons was a “red line” that would prompt action.

Hezbollah — backed by Syria and Iran — wants to upgrade its arsenal in hopes of changing the parameters for any future engagement with the powerful Israeli military, and Israel is determined to stop it. And Hezbollah is perhaps even more anxious to gird itself for future challenges to its primacy in Lebanon, especially if a Sunni-led revolution triumphs next door in Syria.

But if weapons were targeted, analysts said, it is not even clear that they belonged to Hezbollah. Arab and Israeli analysts said another possibility was that Syria was simply aiming to move some weapons to Lebanon for safekeeping. While there are risks for Hezbollah that accepting them could draw an Israeli attack, said Emile Hokayem, a Bahrain-based analyst at the International Institute for Strategic Studies, there is also an upside: “If Assad goes down, they have the arms.”

Elias Hanna, a retired Lebanese general and professor at the American University of Beirut, said that SA-17s made little sense for Hezbollah because they require large launching systems that use radar and would be easy targets for Israel. Syria, he said, needs SA-17s in case of international intervention in its civil war.

Those suggestions comported with the account of a Syrian officer who said in a recent interview that the heavily guarded military area around the Jamraya research facility was used as a depot for weapons being transferred to southern Lebanon and Syria’s coastal government stronghold of Tartous for safekeeping, in convoys of tractor-trailer trucks. (The officer said he had lost faith in the government but hesitated to defect because he did not trust the rebels.)

The attack on Wednesday, in all its uncertainty, pointed to the larger changes afoot in the region. Hezbollah may be looking at a future where it is without Syria’s backing and has to defend itself against Sunnis resentful of its role in the Syrian conflict. And Israel may find that its most dangerous foe is not Hezbollah but jihadist Syrian rebel groups that are fragmented and difficult to deter.

If Syria’s weapons end up with jihadist groups like Al Qaeda or its proxies, that would be a global threat, said Boaz Ganor, executive director of the International Institute for Counter-Terrorism at the Interdisciplinary Center in Herzliya, Israel. “If one organization will put their hands on this arsenal, then it will change hands in no time and we’ll see it all over the world,” he said.