Iran has attacked US bases in the Gulf region in retaliation for the latest round of US strikes, which came after Donald Trump said he would "hit them hard".
US Central Command (Centcom) said it had completed its second day of "self-defense strikes", launched on Wednesday after Trump said Tehran has taken "too long to make a deal" to end the war.
In response, Iran said it had attacked a US bases in Bahrain and Kuwait - which it also said it had targeted after US strikes on Tuesday.
The escalation of tit-for-tat strikes in recent days has tested a fragile ceasefire agreed in April.
After the latest US attack, explosions were heard in cities the south of Iran, near the Strait of Hormuz where US forces hit air defence, radar and other sites on Tuesday.
During Wednesday's flare-up, Iran's Islamic Revolutionary Guards Corps (IRGC) also said it had struck ships in the Strait of Hormuz.
That came after Iranian state media reported that the Strait of Hormuz was "completely closed to all type of vessel". Centcom, however, said "commercial ships are continuing to transit in and out of the Strait of Hormuz".
Two oil tankers passing through the Strait of Hormuz were hit by Iran's navy, Iranian state media reported, although there was no immediate confirmation.
Oil prices rose shortly after the closure of the shipping channel and the apparent attack on the ships was announced.
Brent crude oil, seen as the global benchmark, climbed above $95 a barrel after rising by about 2% during morning trade in Asia.
Hours before the latest US attack was launched, Trump had warned: “We hit them hard yesterday and we're going to hit them hard again today.”
Trump wrote on Truth Social that Iranian leaders have "taken too long to negotiate a deal", while the Iranian foreign ministry accused the US of "damaging the diplomatic process through the contradictory messages it sends".
In response to Trump's comments Iran's president Masoud Pezeshkian said Iran "will stand firm against any pressure or threat".
US Defence Secretary Pete Hegseth later said bombs would be "dropping on key facilities in Iran".
Hegseth said Iran had been given a chance to make a deal but had not taken it, and Trump had said Iran would be attacked again if no peace deal was secured.
In April, the US and Iran agreed a ceasefire that was initially meant to last for two weeks. Both sides have since exchanged intermittent fire, without returning to full-scale hostilities.
However, recent efforts to broker negotiations between Washington and Tehran have stalled and attacks have ramped up.
On Tuesday, a US helicopter was downed in an attack that was blamed on Iran. The IRGC responded by targeting US bases across the Middle East.
In a statement on X, UN Secretary General António Guterres said the Middle East was "being pulled deeper into crisis", and recent attacks meant "the ceasefire is more like a lesser-fire".
"We should not minimize the risks of lesser fire becoming full fire. All parties must work towards a diplomatic settlement. No more attacks. No more excuses," he said in a statement.
Source: BBC
– Agencies
