Iran says it's targeting American military sites in Bahrain and Kuwait in response to US strikes on dozens of Iranian targets.
Late on Tuesday, US Central Command (Centcom) said it had hit more than 80 targets, including over 60 Islamic Revolutionary Guard Corps (IRGC) small boats.
The strikes hit areas including Bandar Abbas and Sirik, leaving some injured by shrapnel, according to Iranian state media.
It followed attacks earlier in the week on three oil tankers in the Strait of Hormuz, which Iran has not directly claimed responsibility for.
Nato chief Mark Rutte says the US strikes were "absolutely necessary", accusing Iran of "basically violating the ceasefire". Iran's parliamentary speaker Mohammad Bagher Ghalibaf says it's the US who breached the truce.
US President Donald Trump is speaking at a Nato summit in Turkey.
Last month, Tehran and Washington signed a 14-page memorandum of understanding, aimed at extending the ceasefire and ending the conflict "on all fronts" - what's in it?
Iran's leaders are a 'cancer' and 'evil', Trump says at Nato summit
Speaking at the Nato summit in Turkey, Donald Trump describes the Iranian regime as "evil people" and calls the administration "crazy", repeating the US position that Tehran can't be allowed to develop a nuclear weapon.
He points to attacks on ships in the Strait of Hormuz on Tuesday, as well as strikes against targets in Kuwait and Bahrain.
"These are evil sick people," the US president continues. "They're cancer, and you know what you have to do - you have to cut out cancer early."
Parts of deal with US 'ineffective' after strikes, says Iran's foreign minister
Iran's Foreign Minister Abbas Araghchi has accused the US of a "flagrant violation" of the memorandum of understanding (MoU).
The US strikes, reinstatement of sanctions on Iranian oil sales and Israel's ongoing conflict with Hezbollah in Lebanon have rendered "important and fundamental parts of the understanding on the cessation of the war ineffective", he says in a statement.
He adds that Iran "will not hesitate" to defend its "integrity, national sovereignty, and national security".
In a warning to Gulf countries which host US military bases, Araghchi says Iran will "target the source and point of origin" of any attacks.
