President Donald Trump announced “major combat operations” against Iran on Feb. 28, with massive joint U.S.-Israeli strikes attack targeting military and government sites, officials said.

Ayatollah Ali Khamenei was among those killed in Tehran on the first day of strikes, with his son Mojtaba Khamenei later chosen to succeed him. Iran has responded with missile and drone attacks targeting Israel, regional U.S. bases and multiple Gulf nations. Iran is also attempting to block some shipping traffic through the Strait of Hormuz.

Israel is also intensifying its long-running strike campaign against the Iran-backed Hezbollah militia in Lebanon and expanding its ground operations in the south of the country.

Watch special coverage on Nightline, “War with Iran,” each night on ABC and streaming on Disney+ and Hulu.