TEHRAN: Iran questioned the seriousness of US diplomacy on Saturday in the wake of renewed naval clashes in the Gulf, while keeping Washington waiting for a response to its latest negotiating position.
US President Donald Trump had said on Friday that he was expecting Iran's answer to Washington's latest proposal for a deal "supposedly tonight".
But if Iran sent Pakistani mediators a response, there was no public sign of it, and Tehran's Foreign Minister Abbas Araghchi called into question the reliability of the US leadership in a call with his Turkish counterpart.
"The recent escalation of tensions by American forces in the Persian Gulf and their numerous actions in violating the ceasefire have added to suspicions about the motivation and seriousness of the American side in the path of diplomacy," he said, according to an Iranian account of the call published by the ISNA news agency.
In an incident on Friday, a US fighter jet fired on and disabled two Iranian-flagged tankers that Washington accused of challenging its blockade of Iran's ports. An Iranian military official told local media the navy had responded with strikes.
That incident followed another flare-up the night before in the Strait of Hormuz, a vital international sea lane that Iran is seeking to control in order to extract tolls and wield economic leverage over the US and its allies.
The US says it is unacceptable for Tehran to control the key oil route.
Washington has sent Iran, via Pakistani mediators, a proposal to extend the truce in the Gulf to allow for talks on a final settlement of the conflict, launched 10 weeks ago with US-Israeli strikes on Iran.
A reporter for French broadcaster LCI, Margot Haddad, said Saturday that Trump had told her in a brief interview he still expected to find out Iran's answer "very soon".
Iran's foreign ministry spokesman said Friday that the proposal was still "under review".
Oil slick
Qatar's prime minister, Sheikh Mohammed bin Abdulrahman Al Thani, met with US Vice President JD Vance in Washington on Friday and discussed the Pakistani-led efforts to broker a permanent peace.
Iran has attacked sites in Qatar during the war, pointing to the wealthy emirate's role as the host of a major US air base.
Meanwhile, satellite images have shown that an oil slick is spreading off the coast of Iran's Kharg Island, a key oil export terminal for the Islamic republic.
It was not immediately clear what had caused the apparent spill, which was off the island's west coast and appeared to cover more than 20 square miles (52 square kilometres), according to global monitor Orbital EOS.
A UK-based non-governmental organisation, the Conflict and Environment Observatory, told AFP that by Saturday the slick was "much reduced", and may have been caused by leaking oil infrastructure.
Kharg Island is at the heart of Iran's oil export industry, a lynchpin of its battered economy, and lies in the Gulf far north of the narrow Strait of Hormuz.
Following the start of the war on February 28, Iran largely closed the strait, throwing global markets into turmoil and driving up oil prices.
The US later imposed its own blockade of Iranian ports in response, and Trump this week abandoned a short-lived US naval operation designed to reopen the strait to commercial shipping.
Britain said on Saturday that it was sending a naval destroyer to the region as part of "prudent planning" for a British- and French-led coalition to facilitate shipping in the Strait of Hormuz once a durable ceasefire is reached.
The British defence ministry said HMS Dragon would strengthen the confidence of commercial vessels and support mine clearance efforts.
Lebanon front
A parallel ceasefire on the war's Lebanon front is also under strain amid daily exchanges of fire between Israel and Iran-backed Hezbollah.
Authorities said eight people were killed in Israeli strikes in southern Lebanon on Saturday, while state media reported air raids targeting a highway south of Beirut, outside the militant group's traditional strongholds.
An AFP correspondent saw two destroyed cars and emergency workers along the road about 20 kilometres (12 miles) from the capital.
Hezbollah, meanwhile, said that it launched a drone at soldiers in northern Israel in retaliation for ceasefire violations.
The Israeli military reported several explosive drones launched into Israel, saying an army reservist was severely wounded and two others moderately injured in one of the attacks.
The fresh strikes come as Lebanon and Israel, officially at war since 1948, are to hold direct negotiations in Washington next week, which Hezbollah vehemently opposes.