Israel struck military sites in Iran early on Saturday, saying it was retaliating against Tehran's strikes on Israel this month.
Iranian media reported multiple explosions over several hours in the capital and at nearby military bases, starting shortly after 2 a.m.
Before dawn, Israel's public broadcaster said three waves of strikes had been completed and that the operation was over.
Iran said its air defense system successfully countered Israel's attacks on military targets in the provinces of Tehran, Khuzestan and Ilam with "limited damage" to some locations.
The Middle East has been on edge awaiting Israel's retaliation for a ballistic-missile barrage carried out by Iran on Oct. 1, in which around 200 missiles were fired at Israel and one person was killed in the West Bank.
Tensions between arch rivals Israel and Iran have escalated since Hamas, the Iran-backed Palestinian militant group based in Gaza, attacked Israel on Oct. 7, 2023. Hamas has been supported by Lebanon-based Hezbollah militants, also backed by Iran.
Fears that Iran and the US would be drawn into a regional war have risen with Israel's intensifying assault on Hezbollah since last month, including airstrikes on the Lebanese capital Beirut and a ground operation, as well as its year-old war in Gaza.
"In response to months of continuous attacks from the regime in Iran against the State of Israel – right now the Israel Defense Forces is conducting precise strikes on military targets in Iran," Israel's military said in a statement announcing the attack.
The military said later it had completed its "targeted" attacks in Iran, striking truck missile manufacturing facilities and surface-to-aerial equipment, adding its planes had safely returned home.
"If the regime in Iran were to make the mistake of beginning a new round of escalation, we will be obligated to respond," the military said.
Iranian authorities have repeatedly warned Israel against any attack.
"Iran reserves the right to respond to any aggression, and there is no doubt that Israel will face a proportional reaction for any action it takes," the semi-official Tasnim news agency said on Saturday, citing sources.
Videos carried by Iranian media showed air defenses continuously firing at apparently incoming projectiles in central Tehran, without saying which sites were coming under attack.
The semi-official Tasnim news agency said Iranian Revolutionary Guard Corps bases that were attacked were not damaged.
A spokesperson for Iran's Civil Aviation Organization said flights on all routes were cancelled until further notice, state news agency IRNA reported. Neighboring Iraq also suspended all flights until further notice, its state news agency said.
Israel said Prime Minister Benjamin Netanyahu, Defense Minister Yoav Gallant and other security officials had closely followed the operation at the military's command and control center in Tel Aviv.
