A tanker sanctioned by the US travelled through the strait of Hormuz on Tuesday, shipping data on LSEG showed, testing the US naval blockade.

The tanker Rich Starry is Chinese-owned and has Chinese crew onboard, Reuters cites the data as showing.

Bloomberg reported earlier in the day that the medium-range tanker – earlier known as Full Star – was blacklisted by Washington in 2023 for helping Tehran evade energy sanctions. It was not clear on this occasion whether it visited Iranian ports before its transit or was carrying cargo.

The report continued:

This exit from the Persian Gulf is a second attempt for the carrier in less than 24 hours. Just as the blockade came into effect, Rich Starry was making its way into the narrow waterway near Iran’s Qeshm Island and turned back – only to restart its exit just hours later, broadcasting that it has a Chinese owner and crew. This is a safety mechanism frequently used by vessels, but will test US resolve to challenge vessels tied to the world’s largest oil importer.

The global shipping community and energy traders have been on edge since Trump announced a naval blockade of Iran beginning on Monday at 10 a.m. New York time, leaving them scrambling to understand the fine print. Most of those reached by Bloomberg across the Middle East and Asia said they would pause moves until the detail of the US blockade – intended to restrict Iran’s capacity to sell its oil – was clear.

Iran has proposed suspending its uranium enrichment for up to five years after the US sought 20 years at the weekend talks in Pakistan, the New York Times is reporting.

It said the Trump administration rejected the five-year offer, citing Iranian and US officials.

The report could be immediately verified.

The Times said that while the US and Iran traded proposals for suspending Iranian nuclear activities during the weekend negotiations, the countries remained far apart on the length of any agreement, according to the officials.

But it said the discussions “suggested that there may be a path to a peace deal”, even as the US began blockading Iranian ports.

Iran criticised the US blockade around its ports on Monday as a “grave violation” of its sovereignty amid the fragile ceasefire.

“The imposition of a maritime blockade constitutes a grave violation of the sovereignty and territorial integrity of the Islamic Republic of Iran,” Iran’s ambassador to the UN, Amir Saeid Iravani, wrote to UN secretary general António Guterres.

The “unlawful” blockade also “constitutes a serious violation of the fundamental principles of the international law of the sea”, Iravani added in the letter, seen by Agence France-Presse.

Donald Trump ordered a blockade of ships entering or leaving Iranian ports and coastal areas in the Gulf that came into force at 1400 GMT Monday, despite the US and Iran agreeing last week to a two-week ceasefire.

Trump warned that any Iranian attack boats that challenged the blockade would be destroyed.

Guterres on Monday called on “all parties” to respect freedom of navigation in the Hormuz strait.

Mediator Pakistan and the gulf state Qatar have continued calls for the truce to be respected as diplomatic efforts continue.

The Lebanese militant group Hezbollah will not abide by any agreements that may result from direct Lebanon-Israel talks in the US, negotiations it firmly opposes, a senior Hezbollah official has said.

Wafiq Safa, a high-ranking member of Hezbollah’s political council, spoke on the eve of talks expected in Washington between Lebanese and Israeli ambassadors to the US.

It will be the first time in decades that envoys from Lebanon and Israel, which do not have diplomatic relations, meet face-to-face in direct talks.

“As for the outcomes of this negotiation between Lebanon and the Israeli enemy, we are not interested in or concerned with them at all,” Safa told the Associated Press.

Separately, the leader of Hezbollah urged Lebanon to pull out of the talks with Israel. Naim Kassem spoke in a televised address on the eve of the scheduled meeting.

The latest round of fighting was sparked by Hezbollah firing rockets into northern Israel on 2 March, after the US and Israel attacked Iran.

At least 2,055 people have been killed in Israeli strikes in Lebanon, the health ,inistry says, among them 252 women, 165 children and 87 medical workers, while 6,588 others were wounded. More than 1 million people have been displaced.

Lebanon’s government – which says it is committed to disarming Hezbollah – had called for direct talks early on in the war. Last week, Israel announced its approval of talks.

Welcome to the Guardian’s continuing coverage of the crisis in the Middle East.

The US blockade of ships using Iranian ports in the Gulf began on Monday, turning the six-week-old conflict between the US-Israeli coalition and Iran into a test of economic endurance.

US Central Command (Centcom) made no formal announcement of the start of the blockade but had said it would take effect at 5.30pm Iranian time on Monday, and would apply to any ships entering or departing Iranian ports or coastal areas. Ships using non-Iranian ports would not be impeded.

Donald Trump claimed that 34 ships had passed on Sunday through the strait of Hormuz, the gateway to the Gulf, but gave no supporting evidence. Speaking to reporters at the White House, the president also claimed: “We’ve been called by the other side,” who he said would “like to make a deal very badly”.

In other key developments:

• Trump said the blockade would be on all Iranian ports along the strait from Monday onward. About 20% of the global oil and gas supply moved through the waterway before the war. Seafarers as well as the United Kingdom Maritime Trade Operations received advisories indicating Trump’s blockade would apply to all ship traffic, regardless of the vessel’s flag.

• Trump claimed that Iran wanted to reach a deal. He insisted the US would not agree to any deal that would permit Iran to have a nuclear weapon. “We can’t let a country blackmail or extort the world,” he said at a last-minute press conference at the White House on Monday.

• After receiving a McDonald’s delivery at the beginning of the presser, Trump invoked bellicose language in discussing Iran. “Iran will not have a nuclear weapon, and we’re going to get the dust back. We’ll get it back, either we’ll get it back from them, or we’ll take it,” he said. At one point, when questioned about some sort of prior ultimatum regarding Iran, Trump said: “I don’t want to comment on that but it won’t be pleasant.”

• Talks are expected in Washington between Lebanese and Israeli ambassadors to the US. It will be the first time in decades that envoys from Lebanon and Israel, which do not have diplomatic relations, will meet face-to-face in direct talks. Lebanese officials are looking to broker a ceasefire in the Israel-Hezbollah war.

• There were reports indicating US officials were continuing talks with Tehran. One official told CNN: “There is continued engagement between the US and Iran and forward motion on trying to get an agreement.” Meanwhile, some administration officials were having internal talks about how a second sit-down with Iranian officials might look should the opportunity arise, the network reported.

• Trump blasted Pope Leo XIV on social media in response to the pontiff’s call for an end to the war. The president claimed the pope was trying to appease the “radical left”. The pope said he had “no intention to debate” Trump over Iran but would continue to advocate for peace. US vice-president JD Vance urged the Vatican to “stick to matters of morality”.