The Israeli army said on Monday that 10 people had been killed during Sunday's "Naksa Day" protests along the Syrian ceasefire line, describing Damascus's toll of 23 as "exaggerated."
Israeli leaders accused Syrian President Bashar al-Assad of encouraging the unrest to divert attention from his crackdown on domestic protests, while Damascus accused Israel of "flagrant aggression."
The United States said it was "deeply troubled" by the violence on the Golan and condemned Syria.
"We condemn what appears to be an effort by the Syrian government to incite events and draw attention away from its own internal issues," said State Department spokesman Mark Toner said.
"Israel, like any sovereign nation, has a right to defend itself."
EU foreign policy chief Catherine Ashton urged a "measured and proportionate response" from Israel and called on Syria to refrain from "provocative actions" following the Golan violence.
Troops in the Golan Heights remained on high alert after Sunday's bloodshed which Syrian state television said killed 23 people and wounded 350 when Israeli troops shot at protesters marking the anniversary of the 1967 Six Day War.
Israel's military said it counted 10 protesters dead -- none of whom was killed by Israeli fire.
"We are aware that around 10 of the casualties that the Syrians reported yesterday were killed by the fact that they used Molotov cocktails in the Quneitra area that hit some Syrian landmines," Lieutenant Colonel Avital Leibovitz told AFP.
"I think there is solid ground to believe that (the Syrian figures) are exaggerated," she said. "A big number of them died as a result of their own deeds."
Israeli Prime Minister Benjamin Netanyahu said troops used live fire as a last resort.
"We used many varied non-lethal means and the firing was a last resort after all other options had been used," the premier told reporters in parliament.
Signup to our newsletter and follow us on Facebook and Twitter!
Netanyahu and Defence Minister Ehud Barak accused Assad of trying to divert attention from his domestic problems.
"Perhaps it is an attempt to divert international attention from the wholesale killing of civilians being carried out in the cities of Syria," Netanyahu said.
"We have no choice, we have to defend our border and Assad, in my opinion will fall in the end," said Barak.
Syria accused Israel of shooting civilians.
"Syria strongly denounces the flagrant attack yesterday on unarmed civilians, Syrian and Palestinians, along the demarcation line in the occupied Golan," a foreign ministry statement said.
"The aggression resulted in a large number of dead and wounded... and unmasks the reality of the state terrorism practised by Israel."
Scene: In Golan, mixed feelings on armistice line protests
Sunday's confrontation erupted as hundreds of protesters from Syria marched towards two points along the ceasefire line -- Quneitra in no-man's land, and Majdal Shams, the Druze town on the Israeli-occupied side of the plateau.
As they began cutting through a line of barbed wire, troops urged them to stop in Arabic and fired tear gas, then warning shots after which they took aim at the lower body, the military said.
The protests coincided with the 44th anniversary of Israel's seizure of the Golan, the West Bank and the Gaza Strip in 1967 Middle East War in an event known in Arabic as the "Naksa" or "setback."
Three weeks earlier, thousands of protesters in Lebanon, Syria and Gaza tried to force their way across the borders in a mass show of mourning over the 1948 creation of the Jewish state, known as the "Nakba" or "catastrophe."
At that time, hundreds forced their way onto the Israeli-controlled Golan prompting troops to open fire killing four, while a similar yet unsuccessful attempt along the Lebanon border left six dead.
Although nobody succeeded in crossing the frontier on Sunday, they ran down a hill into no-man's land on the Syrian side to a ditch filled with barbed wire which had been dug by the Israelis last week, but they were not able to cross it.