Israel killed Hezbollah leader Sayyed Hassan Nasrallah in a powerful airstrike in Beirut, dealing a huge blow to the Iran-backed group as it reels from an escalating campaign of Israeli attacks.

The Israeli military said on Saturday it had eliminated Nasrallah in the strike on the group’s central command headquarters in Beirut’s southern suburbs a day earlier. Hezbollah confirmed he had been killed, without saying how.

His death is not only a major blow to Hezbollah, but also to Iran, removing an influential ally who helped build Hezbollah into the linchpin of Tehran’s constellation of allied groups in the Arab world.