Fallout from the Libyan revolution blew across North Africa and the Middle East on Monday and boosted other popular uprisings in the region, most of which had seen their momentum stall since the exultant early days of the Arab Spring.

In several Syrian cities, thousands of anti-government demonstrators defied a crackdown and warned that country’s president, Bashar al-Assad, that he would meet the fate of Libyan ruler Moammar Gaddafi. “Gaddafi is gone,” they chanted. “Now it’s your turn, Bashar!”

The fight for control of Tripoli was also closely followed 2,000 miles away in Yemen, where demonstrators have watched President Ali Abdullah Saleh flee the country but are still locked in a struggle for power. “The Yemeni opposition is almost there,” said Shadi Hamid, research director at the Brookings Doha Center in Qatar. “They have a very small window of opportunity, and now is the time to take advantage of it.”

In comparison with other places gripped by the Arab Spring, Libya was in many ways an anomaly. Its rebels needed military intervention from NATO and support from other Arab countries, and even then they took more than five months to reach the point of toppling Gaddafi.

But leaders and analysts said Gaddafi’s apparent ouster will serve as a lesson to autocrats elsewhere that they can no longer assume that brutal repression — a time-honored tactic in the region — will defeat a mass opposition movement.

The Libyan example “shows that leaders who do not listen to their people cannot stay in power,” Turkish Foreign Minister Ahmed Davutoglu said Monday.

In Syria, for instance, largely peaceful demonstrations have persisted and spread for many weeks despite a violent response from the military and secret services that has killed more than 2,000 people, according to human rights groups.

“Gaddafi’s capture, I think, would give the Syrians a push, in ways that we cannot comprehend, in the sense that it will be motivational or inspirational,” said Mahmoud Salem, a Cairo democracy activist and blogger who goes by the moniker Sandmonkey. “I don’t think the Syrians will falter.”

The Arab Spring erupted with stunning results in January, when pro-democracy protesters in Tunisia chased their longtime ruler, Zine el-Abidine Ben Ali, into exile. The next month, even bigger crowds in Egypt forced the abdication of President Hosni Mubarak. Both revolutions avoided heavy bloodshed and raised hopes that similar changes would sweep across the rest of the Arab world. But that optimism had steadily faded until Sunday, when Libya’s rebels finally broke a stalemate with Gaddafi and swept into Tripoli.

“What Libya shows us is that not every opposition movement has to follow the Egyptian or Tunisian model,” said Geoff D. Porter, an analyst and head of North Africa Risk Consulting. “If it doesn’t produce results in eight weeks, it doesn’t mean it’s over.”

In Syria, Assad has tried to defuse rising anticipation that he will become the next Arab ruler to fall. In an interview Sunday with Syrian state television, he tried to portray an image of confidence and calm, but also pointedly warned the United States and NATO not to intervene militarily as they have in Libya.

U.S. and European leaders have repeatedly said they have no intention of doing so. While they have called on Assad to step down and imposed sanctions, analysts said he could survive indefinitely as long as his military and security services remain loyal, something that eluded Gaddafi.

Others said the immediate aftermath of the Libyan revolution could have an even more profound influence on uprisings elsewhere.

If the shooting quickly subsides and the Libyan rebels are able to build a functioning central government, it would give further encouragement to protesters in the streets of Damascus and Sanaa. But if Libya descends into factionalism or tribal warfare — with scenes reminiscent of Iraq after the fall of Saddam Hussein — then ardor for the Arab Spring could cool again.

“People are going to be looking at how this plays out very, very closely,” said Jon B. Alterman, director of the Middle East program at the Center for Strategic and International Studies. “It’s easy to agree that the leader must go. It’s much harder to agree on what comes next.”

Some Palestinian activists said that their aspirations, too, had been buoyed by the success of the Libyan rebels but that NATO’s involvement had taken the sheen off the results.

“It is getting a cautious welcome because it was achieved with foreign intervention rather than by the people themselves, as was the case in Egypt,” said Hani al-Masri, a political analyst in Ramallah, West Bank. “Some people are calling it liberation through occupation. The Egyptian experience was inspiring. In Libya, we have to wait and see.”

Mustafa Barghouti, an independent politician in the West Bank who for years has organized popular protests against Israeli occupation, called the Egyptian and Tunisian revolutions “the best model” because they also embraced nonviolence.

“People should have the right to choose their leader freely and democratically, and though in [Libya] it took longer than it should have, the main message is that eventually the people will succeed if they show determination,” he said.

While the outcome of the Libyan revolt remains uncertain, analysts said the sudden turn of events in Tripoli has managed to keep the Arab Spring alive, something that had increasingly fallen into doubt.

“If Gaddafi had prevailed, that would have sent a devastating message elsewhere,” said Robert Malley, director of the Middle East and North Africa program for the International Crisis Group and a former Clinton administration official. “Had he won, it would have been enormously dispiriting to people throughout the region.”

Correspondent Joel Greenberg in Jerusalem and special correspondent Ingy Hassieb in Cairo contributed to this report.