Israel's assassination of Hezbollah's leader, Hassan Nasrallah, has created a very dangerous situation in the Middle East.
Nasrallah was a key figure in Iran's struggle against Israel and its rivals like Saudi Arabia.
Iran now faces a difficult choice: respond with force and risk a wider war, or try to calm things down and avoid further conflict.
The world is watching closely as Iran weighs its options, which could have major implications for the region and beyond.
