Pakistani Foreign Minister Ishaq Dar arrived in Washington on Friday for talks with US Secretary of State Marco Rubio that are expected to include the latest developments in negotiations on ending the Iran war.

A first round of peace talks in Pakistan concluded without a pact, but Reuters cited sources as saying on Thursday that Tehran and Washington had reached an initial agreement to extend a ceasefire announced in April and lift restrictions on shipping through the Strait of Hormuz.

US President Donald Trump, however, has yet to approve the agreement, and Iran's Tasnim news agency reiterated on Friday that it had not been finalized, saying it had undergone changes in recent days.

Dar will meet Rubio at 10 a.m. (GMT-4), according to Rubio's schedule on the US State Department website. Pakistan's foreign ministry, which reported Dar's arrival, said he would fly home later in the day.

While Dar is also deputy prime minister, Pakistan's bid to mediate an end to the Iran conflict, which has killed thousands of people and caused global economic pain by pushing up energy prices, has been led by army chief Field Marshal Asim Munir.

Trump, who has praised Munir, has repeatedly said an end to the war is close since mid-March, though Washington and Tehran have shown little public movement toward common ground.

Iran has called for sanctions to be lifted, foreign assets to be unfrozen, and US forces to be withdrawn from the region, while the United States has called for Iran to dismantle its nuclear program, which Tehran says is for peaceful purposes.

The most urgent issue is the freeing of traffic in the Strait of Hormuz, which carried a fifth of global oil and gas shipments before the conflict.

No oil tankers transited the strait in the past 24 hours, although a Chinese-flagged vehicle carrier did cross. MarineTraffic data, which captures only vessels actively broadcasting their positions, showed at 1200 GMT on Friday.

Several supertankers and liquefied natural gas (LNG) carriers departed earlier this week.

Iranian state television said 24 vessels had passed through the strait in the past 24 hours, reiterating that none would transit without authorization from Iran's Revolutionary Guards.

Pakistan had earlier said Dar's talks with Rubio would focus on bilateral relations and "Pakistan's efforts to promote regional peace and stability through dialog and diplomacy."