The Lebanese militant group Hezbollah was long considered Iran’s first line of defense in case of a war with Israel.

Iran's Revolutionary Guards chief Hossein Salami, who was killed in an Israeli air strike on Tehran Friday, was a veteran officer close to Supreme Leader Ayatollah Ali Khamenei known for his tirades against Israel and its US ally.

The attack comes after decades of mutual hostility and a long-running shadow war of covert strikes and sabotage.

Countries in the region condemned Israel’s attack, while leaders around the globe called for immediate de-escalation from both sides.

Israel launched strikes on Iran’s capital early Friday, with explosions booming across Tehran as Israel said it targeted nuclear and military sites.