The US military launched several "self-defence" strikes against Iran on Tuesday, hours after US President Donald Trump said he would respond to an American attack helicopter being shot down.
The moves mark the latest escalation between the US and Iran and bring fresh risks to a two-month-old ceasefire and fragile talks.
The US military's Central Command said its forces struck Iranian air defence, ground control stations and surveillance radar sites near the Strait of Hormuz with precision munitions from US Air Force and Navy fighter jets.
"The operation was a proportional response to recent attacks on US forces and international commercial ships transiting regional waters," Centcom said in a statement, noting the action came at Mr Trump's direction.
Mr Trump told ABC News that the "response should be very strong, very powerful, and that's what this one is".
Iran's state broadcaster confirmed explosions at Sirik, on the southern coast bordering the Strait of Hormuz, and nearby Qeshm Island.
“Sirik is confirmed to have been hit by a projectile but the location and manner of impact have not been determined,” the state-run Islamic Republic of Iran Broadcasting reported on Telegram.
Six explosions were heard in Qeshm, which were caused by “enemy projectiles from a fighter jet” Irib added.
Centcom said the mission was a "proportional response to unjustified Iranian aggression".
Some US bases in the region were targeted in response to the strikes, Iranian media cited the country's top joint military command, Khatam Al Anbiya, as saying.
Iran's Revolutionary Guards said they attacked the US Fifth Fleet in Bahrain with drones and threatened "more severe responses" if hostilities continued, according to media.
Bahrain's Interior Ministry said a warning siren had been sounded and urged the public to head to safety. Air defences had repelled Iranian attacks, a media adviser to Bahrain's King said soon after in a post on X.
Mr Trump said he had been told by the US military that an Apache helicopter had been brought down overnight while conducting a patrol.
He said the aircraft had two pilots on board and that both were safe and uninjured. A US official told Reuters that a one-way attack drone had taken down the helicopter.
Iran's Foreign Minister, Abbas Araghchi, wrote on X that foreign forces close to Iran's territory are at "constant risk on account of their own human errors, plain accidents or potentially being caught in crossfire".
"To reduce risk, best solution is for them to leave. We prefer language of diplomacy but speak other languages too."
He added that "despite its defeats on the battlefield, the US opted to test our determination".
Earlier, Centcom said two crew members from a US Army AH-64 Apache, which went down near the coast of Oman, had been rescued.
Centcom said the soldiers were rescued within two hours and were stable, adding that the incident is still under investigation.
Mr Trump has struggled to secure a ceasefire for the war he started on Iran, alongside Israel.
Israel on Tuesday conducted renewed air strikes on Lebanon, including on the southern city of Tyre, killing at least nine people and wounding dozens more.
Israel's refusal to end its campaign against Iran-backed Hezbollah has hindered Mr Trump's efforts to extend a tenuous ceasefire in the wider US-Israeli war with Iran into a durable settlement. Tehran has long said any peace deal with Washington depends in part on an end to fighting in Lebanon.
Lizzie Porter contributed to this report
