Iranian Interior Minister Eskandar Momeni visited Pakistan, a key mediator in the conflict that is seeking to rejuvenate diplomacy, but it was unclear what new arrangement might be reached to end the war.
Speaking from the Oval Office, US President Donald Trump gave a dim view on possible talks, saying the United States had "no interest in meeting".
Shipping through the Strait of Hormuz has largely stalled and as the fight for control over the key waterway intensifies, both sides have targeted civilian infrastructure in the region relied on by millions of people.
A barrage of US strikes has not compelled Iran to loosen its grip on the strait, through which about one-fifth of the world's crude oil and natural gas was shipped before the war.
The US continued its air strikes on the Islamic Republic on Tuesday and Iran attacked a tanker in the strait, forcing the crew to abandon the ship.
Iran also kept up attacks against US allies in the region.
Sirens in Bahrain and Kuwait warned residents on Tuesday afternoon of incoming projectiles.
In the Red Sea, Iran-aligned Houthi rebels have opened a new front against Saudi Arabia by declaring a naval blockade of the kingdom, threatening the flow of global oil supplies and trade.
With the Strait of Hormuz blocked up, Saudi Arabia has been relying on a pipeline to the Red Sea to get millions of barrels of oil out to market.
A news agency in Yemen that is run by the Houthi movement, SABA, said on Tuesday that six ships in the Red Sea were forced to reroute after they received warnings from the rebel group.
The claim could not be immediately verified.
Three Houthi officials who spoke on condition of anonymity said the group warned international shipping companies on Monday to avoid transiting in the Bab el-Mandeb Strait, the gateway to the Red Sea at the southern tip of the Arabian Peninsula.
Momeni met Pakistani army chief Field Marshal Asim Munir, according to two officials who spoke on condition of anonymity to discuss the closed-door negotiations.
Momeni later met Pakistani Prime Minister Shehbaz Sharif.
In a statement, Sharif expressed deep concern over the recent escalation between the US and Iran and urged all sides to exercise restraint and avoid actions that could further destabilise the region.
Pakistan's political leadership and Munir played a key role in brokering last month's interim agreement between the United States and Iran.
Pakistani officials have been working to persuade both sides to return to the negotiating table to resolve outstanding issues under the June memorandum of understanding.
Trump told reporters that Iranian officials "want to desperately meet. And until they're ready to meet in a meaningful way, we have no interest in meeting".
He said the US would soon target the area near Pickaxe Mountain - a fortified underground site near one of Iran's primary nuclear enrichment facilities.
A deep level of mistrust persists on both sides.
Iran came under a surprise attack in June 2025 and again in February while it was engaging in nuclear negotiations with the US.
The interim deal unravelled when Iran resumed attacks on ships in the Strait of Hormuz, which was supposed to be reopened under the agreement.
The US military's Central Command said it targeted "Iranian military command centres, maritime capabilities, missile and drone launch sites and air defence systems".
Iranian state media reported that explosions were heard in Fars, Hormozgan, Ilam, Kerman, and Sistan and Baluchistan provinces.
The United Kingdom Maritime Trade Operations centre said a tanker came under attack on Tuesday in the strait off Oman, forcing the crew to abandon the vessel.
Iran's paramilitary Revolutionary Guard claimed the attack as well as two other attacks on ships on Monday in the waterway.
