Gen. Hossein Salami was the chief of one of the country’s most powerful centers, and his death was a tough blow to Iran’s embattled leadership, which has had a series of setbacks in the past 20 months of Middle Eastern war and unrest. Salami rose to power six years ago and had a history of threatening the U.S. and Israel.

Iran’s “Axis of Resistance,” the network of militias it has fostered in the Middle East to help it fight Israel, has become seriously degraded, experts say.