Hezbollah has confirmed that its leader and one of its founding members, Hassan Nasrallah, was killed in an Israeli airstrike in Beirut, Lebanon.

The Associated Press says the killing has sent shockwaves throughout Lebanon and the Middle East, where he has been a dominant political and military figure for more than three decades.

Nasrallah, linked by Israel to numerous deadly attacks on Israeli and Jewish targets, has been on Israel’s kill list for decades.

AP says his assassination significantly escalates the situation in the Middle East.

Hezbollah is backed by Iran, Israel’s chief regional rival.

With the threat of retaliation high, Israel’s Prime Minister Benjamin Netanyahu said the coming days would bring “significant challenges” and warned Iran against trying to strike.

Meanwhile a statement from Hezbollah vowed to “continue the holy war against the enemy and in support of Palestine.”