The first direct high-level negotiations between the United States and Iran since 1979 ended without agreement on April 12 after more than 21 hours of talks in Islamabad, with the status of the Strait of Hormuz emerging as the main obstacle.

US Vice President JD Vance said at a briefing that Iran had rejected the package of proposals put forward by Washington. The American side "laid out in detail its red lines and possible compromises", but Tehran did not accept the terms, Vance said. The trilateral meeting, mediated by Pakistan, ended without results.

Iranian parliamentary speaker Mohammad Bagher Ghalibaf led Tehran's delegation in the marathon session at Islamabad's Serena Hotel. The talks were the first face-to-face meeting between senior American and Iranian officials since the 1979 revolution.

According to Tasnim, Iran put forward a number of initiatives that it said Washington must now analyse. Tehran said it was in no rush to reach a deal.

"The situation in the waterway will remain unchanged until the US agrees to a realistic agreement," the Iranian side said, according to Tasnim. Iranian representatives said they saw no need to accelerate the process.

The core dispute centres on the Strait of Hormuz. Washington demands unrestricted freedom of navigation through the waterway, which carries roughly 20% of global oil and LNG in peacetime. Iran insists on its right to control vessel transit and collect fees, a position backed by emergency legislation being fast-tracked through the Iranian parliament.

Iran's central military command said on April 10, the eve of the talks, that its forces remained "on the trigger" and would "enter a new phase of managing the Strait of Hormuz" and "under no circumstances give up our legitimate rights."

The failure to reach agreement leaves the two-week ceasefire, which expires on April 21, in doubt. Trump said on April 8 that all US military forces would remain deployed around Iran and that if the agreement is not complied with "the shootin' starts, bigger, and better, and stronger than anyone has ever seen before."

It remains unclear whether Washington will pursue further diplomacy or shift to other methods.