JERUSALEM (JTA) — A Syrian rebel group has claimed responsibility for the airstrike in Damascus that killed a Lebanese Hezbollah leader who spent nearly three decades in an Israeli prison.

In a video released Monday on YouTube, the Free Syrian Army denied Hezbollah’s claim that Israeli warplanes violated Syrian airspace and assassinated Samir Kuntar, saying the group struck the residential building in which Kuntar and his colleagues were located. The Free Syrian Army claimed Hezbollah was attempting to demoralize the rebel group by claiming Israel undertook the killing.

Israel has neither confirmed nor denied responsibility for the Sunday morning strike on a building in the Syrian capital, though several Israeli officials praised Kuntar’s death.

Kuntar was released in a 2008 swap for the corpses of Israelis killed in the 2006 Lebanon War, and reportedly had been targeted previously by Israel. In July, an Israeli surveillance plane reportedly bombed a car in Syria, killing five men, in an attack believed to be targeting Kuntar. In September, the U.S. State Department designated Kuntar as a terrorist.

Kuntar, who served 29 years in Israeli prison, was responsible for the deaths of four Israelis, including a 4-year-old girl and her father, in a 1979 attack in Nahariya. He is suspected of planning multiple attacks against Israeli soldiers in the Golan Heights.

Reuters reported that he is believed to have become a commander in Hezbollah since his release from prison, and that Hezbollah has sent many of its members to fight in Syria with troops loyal to President Bashar Assad.

Senior Hezbollah officials vowed to retaliate against Israel.

“(I)f the Israelis think by killing Samir Kuntar they have closed an account, then they are very mistaken because they know and will come to know that they have instead opened several more,” senior Hezbollah official Hashem Safeieddine reportedly said.

Thousands attended Kuntar’s burial in Beirut on Monday.