Pakistan is working to bring the United States and Iran together for a second round of peace talks in the coming days as the standoff over the Strait of Hormuz threatens to reignite hostilities, according to sources speaking with US media.

Two US officials, speaking on condition of anonymity, said on April 13 that discussions about a new round of negotiations were under way and that talks could take place as early as April 17, though the venue, timing and composition of delegations had not been finalised. Two Pakistani officials said the first round of talks was part of an ongoing diplomatic process rather than a one-off effort.

The war, now in its seventh week, has killed at least 3,000 people in Iran, more than 2,000 in Lebanon, 23 in Israel and more than a dozen in Gulf Arab states. Thirteen US service members have also been killed.

The US blockade of Iranian ports, which took effect on April 13, saw tankers approaching the strait turn around shortly after it was announced. One vessel, the Rich Starry, later transited the waterway on April 14.

The tanker had been waiting off the UAE coast and is listed by the US Treasury's Office of Foreign Assets Control as linked to Iranian shipping. Lloyd's List, citing ship registry data, reported the vessel is owned by a Chinese shipping company and ultimately bound for China.

US Central Command did not respond to questions about the vessel. It said on April 13 that the blockade applied to ships travelling to and from Iranian ports.

President Donald Trump said Iran's control of the strait amounted to blackmail and warned that any Iranian fast attack ships approaching the blockade would be "immediately eliminated."

Iran's parliamentary speaker Mohammad Bagher Ghalibaf responded in a statement addressed to Trump: "If you fight, we will fight."

Iran has threatened to retaliate against Persian Gulf ports if attacked. The blockade is intended to pressure Tehran, which has exported millions of barrels of oil, mostly to Asia, since the war began, with much of it carried by vessels evading sanctions oversight.

Separately, direct talks between Israel and Lebanon were set to begin in Washington on April 14, the first such negotiations in decades. Israel has continued its air and ground campaign in Lebanon, insisting the ceasefire does not apply to fighting there, though it has halted strikes on Beirut since April 8.

Hezbollah said on April 13 it would not abide by any agreements resulting from the talks.