BEIRUT - A Lebanese man convicted of one of the most notorious attacks in Israel's history and who spent nearly three decades in an Israeli prison has been killed by an Israeli airstrike near the Syrian capital, the Lebanese Shiite Hezbollah group said Sunday.

Hezbollah officials have pledged to avenge the killing of Samir Kantar, sparking fears of escalation in an already volatile region. In a possible first response, three rockets were fired into Israel from Lebanon late Sunday.

Kantar had said that he had been working, with the backing of Hezbollah, to set up "the Syrian resistance" to liberate the Golan Heights, which Israel captured from Syria in 1967 and annexed 14 years later.

Hezbollah said Kantar was killed along with eight others in an airstrike in Jaramana, a suburb of the Syrian capital Damascus, on Saturday night. According to Hezbollah's Al-Manar TV, two Israeli warplanes entered Syrian airspace and fired four long-range missiles at the residential building in Jaramana. It aired footage of what it said was the building, which appeared to be destroyed. Kantar's brother, Bassam, confirmed his "martyrdom" in a Facebook post on Sunday.

In Lebanon, Kantar is known as "the dean of Lebanese prisoners," a reference to his long jail sentence.

In Israel, he gained notoriety for the kidnapping and killing of a man named Danny Haran and his 4-year-old daughter in the coastal town of Nahariya. Kantar was 16 at the time, and a member of the militant Palestine Liberation Front.

He also killed a policeman during the attack, and is alleged to have beaten the 4-year-old to death with a rifle butt. As the attack unfolded, the girl's mother hid inside a crawl space inside their home and accidentally smothered their crying 2-year-old daughter, fearing Kantar would find them.

Kantar was imprisoned in 1979 in Israel and sentenced to three life terms, but was released as part of a prisoner swap with Hezbollah in 2008. While many in Israel were outraged at his release, in Lebanon he received a hero's welcome and the following year he was awarded Syria's highest medal by Syrian President Bashar al-Assad.

Kantar's killing would mark the first Israeli assassination of a senior figure inside Syria since Russia launched its military operations in Syria on Sept. 30 in support of Assad.

Israel and Russia have set up a communications channel to make sure their air forces do not clash with each other, though it was not known whether the alleged Israeli strike on Kantar had been announced to the Russians ahead of time.

In the Russian operation, air raids killed dozens of people in northwestern Syria on Sunday, activists and residents said, two days after the adoption of a U.N. Security Council resolution backing a peace process to end the country's devastating civil war.

The incident coincides with a report released Sunday by Human Rights Watch that accuses Russia and the Syrian government of using cluster bombs - indiscriminate scattershot munitions - that have killed dozens of civilians in Syria in recent weeks.

As many as nine airstrikes hit the rebel-held city of Idlib on Sunday morning, killing at least 36 civilians and insurgents, said Rami Abdurrahman, who heads the Britain-based Syrian Observatory for Human Rights.

This article contains information from the Washington Post.