Hostilities between the United States and Iran has flared again as new US strikes on Iranian targets and reports of attacks in the Gulf raised concerns about the durability of their fragile truce.
Bahrain reported an attack involving several Iranian drones early on Saturday while a UK maritime security agency said a merchant vessel had been struck by an "unidentified projectile".
The circumstances surrounding the ship attack were not immediately clear.
The framework agreement between Iran and the US, which took effect last week, had eased tensions in the war that has gripped the region since US and Israeli attacks on Iran began on February 28.
The deal envisages an end to the fighting and the reopening of the Strait of Hormuz, a vital artery for global oil trade.
But, for the first time since the agreement was signed, the US military struck sites in Iran overnight.
The US Central Command said the attacks targeted Iranian missile and drone storage facilities as well as coastal radar installations.
CENTCOM said those attacks were in retaliation for an Iranian drone strike on a commercial cargo vessel in the Strait of Hormuz on Thursday.
The tit-for-tat escalation continued on Saturday.
Iran's Islamic Revolutionary Guard Corps said its naval forces had attacked US targets in the region in retaliation for the overnight strikes.
The claim could not be independently verified and has not been confirmed by the US.
Iran's foreign ministry condemned the US operation as a "blatant violation" of the framework agreement.
US President Donald Trump, for his part, had previously blamed Iran for the attack on the merchant vessel, describing it as a "foolish" breach of their deal.
The framework accord is intended as a starting point for broader negotiations over the next 60 days, focusing in part on Iran's disputed nuclear program.
The Wall Street Journal quoted a senior US official as saying the ceasefire remained in effect despite the latest hostilities, describing the US strikes solely as retaliation for the attack on the cargo ship.
Nevertheless, the renewed violence has cast doubt on prospects for the planned talks.
Iranian media reported explosions overnight in the southern city of Sirik in Hormozgan province, near the Strait of Hormuz.
The state broadcaster IRIB also reported projectile impacts on Qeshm Island.
Several US media outlets, citing an unnamed US official, said six US Air Force fighter jets struck four Iranian positions along the Strait of Hormuz and on Qeshm Island in an operation lasting about 90 minutes.
The latest escalation followed an attack on a merchant vessel in the Strait of Hormuz on Thursday.
According to the US military, Iran struck the Singapore-flagged ship with a drone as it was leaving the waterway along the Omani coast.
The incident occurred hours after Iran's Revolutionary Guards warned that safe passage through the strait would only be guaranteed along routes designated by Iran.
In response, the United Nations' International Maritime Organisation temporarily suspended operations to escort stranded seafarers.
The organisation said 2500 sailors had been allowed to leave the Strait of Hormuz before the mission paused.
Following the outbreak of US and Israeli attacks on Iran in early March, Iran had largely blocked shipping through the strategic waterway through threats and military action.
The United States responded with its own naval blockade targeting vessels entering or leaving Iranian ports.
Both measures were lifted under the framework agreement.
