Updated

Prime Minister Benjamin Netanyahu on Sunday led a chorus of Israeli officials expressing outrage over the bloodshed in Syria, accusing Iran and Lebanese Hezbollah militants of complicity in the carnage there.

Israel is anxiously watching developments in the neighboring country, fearing widening instability in the region. With dozens killed in ferocious weekend battles, a string of top Israeli officials sounded alarms over the deteriorating situation in Syria and called for international intervention.

Netanyahu accused Syria's powerful, anti-Israel allies of helping the regime of President Basher Assad to brutally suppress the 15-month-old rebellion.

"This massacre is not executed by the Syrian government alone; it is assisted by Iran and Hezbollah, and the world should realize this is a concentrated axis of evil: Iran, Syria and Hezbollah," Netanyahu said at the start of the weekly Cabinet meeting.

After keeping quiet in the early months of the Syrian uprising, Israeli leaders have grown increasingly outspoken in their calls for Assad to step aside. Israeli officials, however, adamantly reject suggestions that they are assisting Syrian rebels.

Vice Prime Minister Shaul Mofaz warned that Iran and Hezbollah could take the conflict beyond Syria's borders, and portrayed the slaughters in the harshest of terms.

"A crime against humanity, genocide, is transpiring in Syria today," Mofaz said in an interview with Army Radio, faulting world powers for what he called a "limp" response and singling out Russia because it is arming Syria.

President Shimon Peres also urged world powers to intervene, telling Israel Radio the international community was not doing enough to end the bloodletting.

"I have much respect for the rebels, who demonstrate daily in face of live gunfire, and I hope they triumph," Peres prior to leaving for the US to receive the Presidential Medal of Freedom at a formal ceremony at the White House.

The U.N.'s latest estimate is that 9,000 people have died in Syria's conflict but that is from April and the world body has been unable to update the figure since. Syrian activists put the toll at more than 13,000.