The conflict between Iran, Israel and the United States intensified as Iranian officials delayed naming a new supreme leader following the killing of Ayatollah Ali Khamenei, citing security concerns. Israel threatened major strikes on the southern suburbs of Beirut, signaling that Lebanon, where Hezbollah is based, is emerging as another front in the widening war. European governments increased military deployments to the Middle East to protect citizens and key shipping routes, while distancing themselves from direct involvement in attacks on Iran.

Israeli and United States forces continued strikes on Iranian military infrastructure, with Israel claiming it had destroyed most of Iran's air defenses and missile launchers. Iran said its retaliatory attacks were acts of self defense, but recent strikes have hit American embassies, energy facilities, airports and hotels across the Persian Gulf. A United States submarine also sank an Iranian naval vessel near Sri Lanka, killing dozens of sailors.

In Washington, the House of Representatives narrowly blocked an effort to limit President Donald Trump's authority to continue the war without congressional approval. Meanwhile, global oil prices surged and stock markets fell, heightening fears of rising inflation and broader economic disruption as the conflict deepens. At least six American service members have been killed in recent Iranian attacks, according to the Defense Department.