Israeli troops opened fire as hundreds of Palestinian protesters and supporters from Syria tried to cross the frontier with the Israeli-held Golan Heights on Sunday. The official Syrian news agency said 23 people were killed and more than 350 injured.

The protest near the Golan Heights and other demonstrations in the West Bank and Gaza Strip marked the anniversary of the outbreak of the 1967 Middle East war, in which Israel captured those territories.

Israeli army spokesman Brig. Gen. Yoav Mordechai accused Syria of creating “a provocation” at the border to distract attention from the Syrian government’s deadly crackdown on the uprising in that country.

In a sign of official backing for the protests, the border clashes were broadcast live on Syrian television, with comments from participants, and reporters were permitted direct access to the normally closed frontier zones.

Across from the Druze village of Majdal Shams in the Golan Heights, hundreds of protesters, many of whom arrived from Damascus, the Syrian capital, streamed down a hillside and marched toward the frontier, carrying Palestinian and Syrian flags and chanting “Palestine is Arab!” and “the Golan is Syrian!”

Unlike a similar effort last month, in which marchers from Syria caught the Israeli army unprepared and breached the frontier, soldiers Sunday had been waiting for the demonstrators and used gunfire to hold them back.

When scores of marchers tried to cross a trench and earth berms topped with razor wire that had been put up by the Israeli military to block their approach, army sharpshooters opened fire from a border fence about 150 yards away.

The army spokesman said troops had fired warning shots before shooting at the legs of the demonstrators. The gunfire was accompanied by loudspeaker warnings in Arabic that anyone who approached the border fence was “endangering himself.”

Despite the intermittent gunfire, scores of protesters continued to stream toward the border, planting flags and holding a mass prayer behind the earth berms. Other groups of protesters carried off casualties, struggling back up the hillside in Syrian territory.

Another confrontation developed near the abandoned Syrian border town of Quneitra, where scores of protesters gathered on rooftops and near the fence with the Golan Heights, some hurling stones at Israeli soldiers, who responded with tear gas, stun grenades and warnings delivered via loudspeaker that “anyone who tries to cross the border will be killed.” Troops later opened fire when the crowd surged toward the border.

The Syrian Arab News Agency said that a local hospital had received the bodies of 23 people and that more than 350 were injured, some critically. The Israeli army said earlier in the day that it knew of 12 casualties.

“There are extremist forces around us who are trying to breach our borders and threaten our communities and citizens,” Israeli Prime Minister Binyamin Netanyahu said in remarks before the weekly meeting of his cabinet. “We will not allow them to do so. I have instructed the security forces to act with the maximum restraint possible but with determination to protect our sovereignty, borders, communities and citizens.”

Mahmoud Safadi, a resident of Majdal Shams who watched the confrontations, said the army had responded with excessive force. “People come unarmed to express their anger peacefully and they are confronted by snipers who shoot them,” he said. “There’s no tear gas or rubber bullets. Just live fire.”

Shortly before sunset, troops fired heavy volleys of tear gas to clear out the protesters, pushing many of them back. That set off stone-throwing by villagers at Majdal Shams, who had gathered near the border throughout the day, chanting slogans and waving Palestinian and Syrian flags.

In the West Bank, Israeli forces clashed with stone-throwing protesters for hours near the Qalandiya checkpoint between Ramallah and Jerusalem, using tear gas, stun grenades and rubber bullets, after a march toward the checkpoint was blocked. At least 10 people were reported injured.

An attempt to march toward the Israeli settlement of Elon Moreh near Nablus was also broken up by troops.

In the Hamas-ruled Gaza Strip, police prevented a few hundred demonstrators from approaching the border with Israel near the Erez Crossing, in an effort by the government to avoid an escalation along the frontier.

Despite the reported casualty toll, the scope of Sunday’s protests was more modest than the coordinated marches May 15, when thousands of Palestinians converged on Israel’s borders from Syria, Lebanon, the West Bank and the Gaza Strip to mark the anniversary of the establishment of Israel in 1948 and the Palestinians’ displacement in the war that followed. Fourteen people were killed after the frontier was breached in the Golan and protesters approached the border fence in Lebanon.

The Israeli-Lebanese frontier was quiet Sunday, after planned protests were canceled under pressure from the Lebanese government. The Lebanese army declared the border a closed military zone. Media reports from Lebanon said diplomats from the United States and the United Nations had pressed Lebanese authorities to prevent a recurrence of last month’s deadly clashes.

Sockol is a special correspondent. Special correspondent Sufian Taha in Qalandiya contributed to this report.