Syrian police set up a pair of checkpoints near the border area, including one just half a mile (one kilometer) away. Nearly 20 protesters, some waving Syrian flags, began walking down a hill leading to the frontier from Syria, when two police officers blocked them from advancing by extending their arms.
It was not clear why Syrian security forces were intervening Monday to prevent a new outbreak of violence. A day earlier, protesters had passed by Syrian and U.N. outposts on their way to the frontier.
Israeli Defense Minister Ehud Barak suggested that the Syrian regime might have instigated Sunday's border unrest — and a similar incident three weeks ago — to deflect attention from its violent crackdown on opposition forces at home.
Israeli Foreign Ministry spokesman Yigal Palmor said Israel plans to file a complaint to the U.N. later Monday "concerning the Syrian regime's cynical manipulation of its own citizens in order to generate violent incidents on the border."
Barak also predicted that Syrian President Bashar Assad has been irreparably weakened by the popular uprising. "I think Assad will fall," Barak told Israel Radio on Monday.
Human rights groups say more than 1,200 people have died in the crackdown against anti-government protesters in Syria since March. Assad has coupled military operations with symbolic overtures toward the opposition, including an amnesty for many prisoners and a call for national dialogue.
The instability in Syria, Barak said, rules out prospects for renewing peacemaking at this time. Israel and the Syrians last held talks in 2008, but they broke down upon the outbreak of Israel's war in the Gaza Strip.
As its price for peace, Syria demands a return of the Golan, a strategic plateau overlooking northern Israel that Israel captured from Syria in 1967 and annexed 14 years later. The annexation is not internationally recognized.
With calm prevailing on the frontier on Monday, Israeli troops repaired a coil of barbed wire that protesters had cut through on Sunday to enter a trench in a buffer zone that Israel had dug after an earlier round of border violence three weeks ago.
Israel had fortified the border after it was breached in the earlier round of unrest. Although protesters did not make it through the border on Sunday, Syrian TV reported that Israeli soldiers shot dead 20 people and wounded hundreds more when they opened fire to block protesters from entering the Golan.
The bodies of people killed Sunday were taken in ambulances from the Martyr Mamdouh Abaza hospital in the Syrian border town of Quneitra and headed north on the highway leading to the capital, Damascus. The convoy of ambulances was accompanied by dozens of cars and buses carrying hundreds of people waving Palestinian flags.
Both Palestinian governments — the Western-backed Palestinian Authority in the West Bank and the anti-Israel Hamas government in Gaza — praised the protesters.
Azzam Ahmed, a top aide to Palestinian President Mahmoud Abbas, accused Israel of "brutally" attacking peaceful Palestinians who "have the right to return to their homes and land."
In Gaza, Hamas ordered three days of mourning, calling the dead "martyrs of Palestine."
Israeli opposition lawmaker Binyamin Ben-Eliezer, a former general and defense minister, predicted the unrest would proliferate across Israel's various borders.
"There is only one solution," said Ben-Eliezer, whose Labor Party splintered, then quit the government in frustration over its failure to break a stubborn impasse in peacemaking with the Palestinians. "To recognize a Palestinian state and sit down tomorrow at the bargaining table," he told Israel Radio.
Sunday's unrest marked the anniversary of the Arab defeat in the 1967 Middle East war, when Israel captured the Golan Heights from Syria, the West Bank and east Jerusalem from Jordan, and the Gaza Strip and Sinai peninsula from Egypt in six days of fighting.
The recent protests have drawn attention to the plight of Palestinian refugees who fled or were expelled from homes in Israel during the war over Israel's 1948 creation. The original refugees, and their descendants, now number several million, and they demand "the right to return" to the families' former properties.
Israel opposes their repatriation because Palestinians would eventually outnumber Jews in the Jewish state. The fate of the refugees and their descendants is one of the toughest issues in any future Israeli-Palestinian peace accord.