Hezbollah’s Sayyed Hassan Nasrallah, Dec. 27, 2015
Lebanon's Hezbollah leader Sayyed Hassan Nasrallah addresses supporters via a screen in Beirut's southern suburbs during a commemoration service Dec. 27, 2015, marking one week since the killing of Hezbollah militant leader Samir Kantar. Reuters/Aziz Taher

The leader of Lebanon's Hezbollah group said Sunday that Israel miscalculated by killing prominent militant Samir Kantar in Syria last week, adding that retaliation for his death was inevitable, whatever the consequences. Sayyed Hassan Nasrallah, speaking at a ceremony to mark a week since Kantar's death in an airstrike on a residential quarter of Damascus, said Israelis should brace themselves for a response either inside or outside Israel.

"The Israelis should be justifiably worried... They should be worried along the border, inside (Israel) and outside," Nasrallah said. "The response is coming no matter what ... We cannot forgive the shedding of our mujahideen blood by the Zionists ... anywhere in the world," he said. Israel has welcomed Kantar's death, but has not confirmed it carried out the airstrike that killed him.

Israeli Defense Minister Moshe Yaalon said Saturday Israel took seriously a possible retaliation over Kantar's killing and accused Iran, Hezbollah's backer, of trying to open "a terrorist front on the Golan Heights.” Yaalon said Hezbollah should be mindful of the 2006 Lebanon war, when Israel responded to a spate of cross-border attacks by the militant group with a large-scale air, ground and sea offensive.

Kantar was jailed in Israel for his part in a 1979 raid in the country that killed four people while he was a member of a Palestinian militant group. Kantar was repatriated to Lebanon in 2008 in a prisoner swap with Hezbollah, which he then joined.

Nasrallah who described Kantar as a "leader" in Hezbollah for the first time acknowledged that Kantar had played a key role in creating a "popular resistance" in Syria against what he said were Israeli designs on the Syrian Golan Heights.

Hezbollah is fighting on the side of President Bashar Assad in the Syrian Civil War. Syrian state media said Kantar was involved in a major offensive this year in Quneitra, near the Israeli-occupied Golan Heights.

Kantar's growing military role in the strategic area had unnerved Israel, Nasrallah said.

Israel seized part of the Golan Heights from Syria in the 1967 Six-Day War and annexed it later.