Israel and Iran have opened a new chapter in their long history of conflict. Israel launched a major attack with strikes early Friday that set off explosions in the Iranian capital of Tehran.

For quite some time now, Iran has pledged to destroy Israel while it supported regional groups that have declared Israel their enemy. Israel, on its part, views Iran as an existential threat and has vowed to prevent it from building a nuclear bomb.

Hossein Salami, the commander of Iran’s elite Islamic Revolutionary Guard Corps (IRGC), was among the senior Iranian officials killed in Israel’s sweeping air strikes that began on Thursday.

The targeted assassinations mark one of the most significant developments in the long-running shadow war between the two regional rivals, sending shockwaves across the Middle East and prompting global concern over the potential for a broader conflict.

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