Israeli forces fired at pro-Palestinian protesters on the Syrian frontier on Sunday as they tried to breach the border for the second time in three weeks, reflecting a new mode of popular struggle and deadly confrontation fueled by turmoil in the Arab world and the vacuum of stalled peace talks.

Wave after wave of protesters, mainly Palestinians from refugee camps in Syria, approached the frontier with the Israeli-controlled Golan Heights. Israeli soldiers opened fire on those who crossed a new trench and tried to attack the border fence near the towns of Majdal Shams in the Golan Heights and Quneitra in Syria.

By nightfall, the Syrian news agency SANA reported that 22 protesters had been killed and more than 350 had been wounded. Israeli officials said that they had no information on casualties but suggested that the Syrian figures were exaggerated.

Even so, it was the worst bloodshed in the Golan Heights since Israel and Syria fought a war there in 1973.

The protest, on the anniversary of the start of the 1967 Middle East war, followed a larger, coordinated assault by demonstrators three weeks ago on four fronts — Syria, Gaza, Lebanon and the West Bank — and attempts on two others, Egypt and Jordan, that were thwarted by those governments.

This time, Lebanon and the Hamas government in Gaza kept protesters away from their borders, and the turnout was low in the West Bank.

The focus was on Syria, where thousands of protesters tried to force their way across the border. Syria’s decision to allow the protest appeared to reflect a calculated strategy to divert attention from its own antigovernment uprising.

Still, the protesters said they counted the day a success because they drew Israeli fire on unarmed demonstrators, generating outrage at Israel. At a time when the peace process is already strained, that reaction is likely to increase international pressure on Israel to create the conditions for resumed negotiations with the Palestinians, and to bolster support in the United Nations for the Palestinian appeal for statehood.

The young protesters, disillusioned with the stymied peace talks and continued Israeli settlement building, say they believe they have hit on a new tactic that at least achieves something, if at a cost, and they intend to repeat it.

“The plan is to clash with the soldiers now,” said Muhammad Abu al-Nassar, 25, who was protesting at a West Bank checkpoint. “We believe that unarmed popular resistance is the best form of ending the occupation.”

Israeli officials, who say they tried every nonlethal method of crowd control at their disposal before resorting to live fire, worry about being cast as the villain but admit they are in a bind.

“What would any country do if people from an enemy country were marching on its borders?” asked Dan Gillerman, a former Israeli ambassador to the United Nations. “We tried all other possible means to stop them.”

At the weekly cabinet meeting, Prime Minister Benjamin Netanyahu said he would not allow “extremist elements” to penetrate Israel’s borders. “I have instructed the security forces to act with determination, with maximum restraint, but with determination to maintain our sovereignty, our borders, our communities and our citizens,” he said.

A military spokeswoman, Lt. Col. Avital Leibovich, said that Israeli forces warned the protesters not to approach the border, in Arabic with megaphones; used nonlethal riot dispersal means like tear gas, which failed to deter them; and then fired warning shots in the air.

When the demonstrators reached the fence, soldiers were “left with no choice,” she said, “but to open fire at the feet of the protesters.”

Syria’s role also creates a quandary for Israel. Although the countries technically remain in a state of war, Syria has kept the border quiet for 37 years.

Protesters there could not have approached the border without government acquiescence, and analysts said the decision to allow the protest was aimed at deflecting attention from the protests sweeping Syria against the government of President Bashar al-Assad.

“I would note that these protests were carried live on Syrian television” an Israeli official said. “They do not carry the protests against their own regime live. They made a decision to try to exploit this for their own purposes.”

The official spoke anonymously because, he said, Israel did not want to allow the protests to stoke tensions with Syria.

But even revived peace talks with the Palestinians would be unlikely to alter Mr. Assad’s calculations.

“Only the Syrian government can stop this, and we do not have leverage over them,” said Shlomo Brom, a retired general at the Institute for National Security Studies at Tel Aviv University.

The protests marked the anniversary of the 1967 war, which Palestinians call the “naksa,” or setback, when Israel captured territory including the West Bank, Gaza and the Syrian Golan Heights.

Last month, President Obama laid out broad principles for negotiations toward a Palestinian state based on the borders before that war, with mutually agreed land swaps. He suggested that talks focus first on borders and security, and deal later with the contentious issues of the status of Jerusalem and the fate of Palestinian refugees from the 1948 war and their descendants.

Israel has rejected the idea of talks based on the 1967 lines and has not yet responded to a French proposal to attend a peace conference in Paris next month. In the absence of talks, the Palestinian leadership plans to seek international recognition for statehood at the United Nations this fall.

The protesters see the failure of talks as justification for a renewed unarmed struggle. But whether border-crashing will become the tactic of choice for a new intifada, or uprising, was unclear.

The protests in the Palestinian territories on Sunday were smaller and more isolated than those last month. In Gaza, only a few dozen Palestinians tried to walk to the Erez checkpoint, and Hamas forces stopped them well before the border.

Activists in Lebanon canceled plans to march to Israel’s northern border after Lebanese authorities declared the area a closed military zone.

In the West Bank, scores of Palestinian youths marched toward the Qalandiya checkpoint, the main gateway between Ramallah and Jerusalem. Israeli troops fired tear gas and sound bombs. Some of the youths had slingshots and hurled stones at the soldiers, who responded with more tear gas and, according to some reports, rubber bullets.

Inspired by the so-called Arab Spring and aided by social networking sites like Facebook and Twitter, the protesters hope their approach will catch on.

“What we are seeing now are trial runs,” Ehud Yaari, a leading Arab affairs analyst, said in an interview. “They have reached the conclusion that there is a powerful weapon that had not been used so far.”