At least two waves of multiple explosions were heard in Iran's capital Tehran and nearby military bases on Saturday, according to semi-official Iranian media.
Israel Defence Forces (IDF) said it had completed its retaliatory strikes in Iran, after announcing it was conducting "precise strikes" on military targets.
The attacks were downplayed by Iran's state media in initial reports, which highlighted Iran's air defences.
Iran state TV said at least six blasts were heard around the capital Tehran, but the scope of the attack was not immediately clear.
Strikes target Iran
Iran's semi-official Iranian Fars news agency said several military bases in the west and south-west of Tehran had been targeted by Israel.
Iranian state media reported that strong explosions were heard around Tehran and nearby Karaj.
The Tasnim News Agency said Islamic Revolutionary Guard Corps bases that were attacked were not damaged.
Iran said its air defence system successfully countered Israel's attacks and "limited damage" was caused to some locations.
In a statement, the Iranian air defence said Israel attacked military targets in the provinces of Tehran, Khuzestan and Ilam.
IDF spokesperson Rear Admiral Daniel Hagari posted a statement on X confirming the strikes.
"The regime in Iran and its proxies in the region have been relentlessly attacking Israel since October 7th — on seven fronts — including direct attacks from Iranian soil," he said.
"Like every other sovereign country in the world, the State of Israel has the right and the duty to respond.
The IDF said in a statement it struck missile-manufacturing facilities in Iran.
A US official said targets did not include energy infrastructure or nuclear facilities.
Iran's aviation authority said it had suspended all flights until further notice, after Israel announced it was conducting strikes in the country.
"Flights on all routes have been cancelled until further notice," the spokesperson of the Civil Aviation Organisation said, according to the official IRNA news agency.
Iran state TV said there has been no fires or explosions at the Tehran oil refinery.
State TV said the origin of the explosions "could be from the activation of Iran's air defence system," citing unnamed Iranian intelligence officials
Explosions heard in Syria
Syrian state news agency SANA said Israel conducted an air attack on Saturday from the occupied Golan Heights and Lebanon, targeting military positions in Syria.
The agency said the attack at around 2am local time had targeted positions in central and southern Syria, citing an unnamed military source.
Syrian state TV said explosions were also heard in the Damascus countryside and central region.
SANA reported Syrian air defences intercepted "hostile targets" near Damascus early on Saturday, as Israel said it was launching strikes in Iran.
"Our anti-aircraft defence is confronting hostile targets in the skies around Damascus," SANA said on Telegram.
Israel has not confirmed striking Syria.
The IDF has been planning a response to a ballistic-missile barrage carried out by Iran on October 1, Tehran's second direct attack on Israel in six months.
"We understand that Israel is conducting targeted strikes against military targets in Iran as an exercise of self-defence and in response to Iran's ballistic missile attack against Israel on October 1st," White House National Security Council spokesperson Sean Savett said.
US 'informed' of strikes beforehand
Israeli strikes on military targets in Iran are "an exercise of self-defence" following Tehran's ballistic missile attack earlier this month, the United States said late Friday.
A US defence official told AFP that Washington was "informed beforehand" and there was "no US involvement" in the strikes.
A senior Biden administration official added that Israel's strikes on Iran appeared to have been a targeted and proportional response to Tehran's earlier attacks, with low risk of civilian harm.
Wires