US and Iran end talks after 21 hours in Islamabad; what happens next?

The failure to reach an agreement in the latest round of U.S.-Iran talks has raised concerns about whether the two-week ceasefire brokered by Pakistan can be maintained, after both sides agreed to it on Tuesday (April 7).

Cause: U.S. “red lines” vs. Iran’s nuclear demands

Both sides blamed each other for the breakdown. U.S. Vice President JD Vance, who led the American negotiating delegation, said the U.S. returned to Washington “without a deal,” adding that Washington had “clearly stated” its red lines.

Vance said Tehran had not accepted U.S. conditions, including a demand that Iran not develop a nuclear weapon. He said the U.S. requires an unequivocal commitment that Iran will not pursue a nuclear weapon or capabilities that could help it quickly manufacture one.

Vance said the U.S. position reflects the core objective of U.S. President Donald Trump and the focus of Washington’s negotiation approach.

Iranian outlets, including Tasnim News Agency, said the American demands were “excessive” and the main obstacle to reaching an agreement. Other Iranian media reported that some differences narrowed, but the Hormuz Strait and Tehran’s nuclear program remained the two biggest points of disagreement.

Development: First direct talks in more than a decade

The Islamabad round followed the ceasefire reached earlier in the week and marked the first direct contact between the U.S. and Iran in more than a decade, and the highest-level dialogue between the two sides since the 1979 Islamic Revolution.

Iran’s Foreign Ministry spokesperson said the talks took place in an atmosphere of distrust, and Iranian media quoted the spokesman as saying that failing to reach an agreement after only one round of talks was “not surprising.”

In a brief press conference after the talks, Vance did not address whether traffic through the Hormuz Strait—described as the shipping lane carrying about 20% of global oil traded—would be reopened. Tehran has blocked the strait since the outbreak of the conflict.

Vance said he had spoken with President Trump about a dozen times during the negotiations. Trump, however, told reporters on Saturday (April 11) that whether an agreement is reached “makes no difference” to him, saying, “we have won.”

Data and logistics: Shipping through Hormuz during the ceasefire

Despite unresolved differences in Islamabad, shipping data showed that on Saturday three supertankers carrying oil passed through the Hormuz Strait. These were described as potentially the first ships to leave the Gulf since the ceasefire was established.

Even so, hundreds of other oil tankers remained stuck in the Gulf, waiting to pass through the strait during the two-week ceasefire.

Negotiation positions and assets dispute

Before the talks began, a senior Iranian source told Reuters that the U.S. had agreed to release Tehran’s assets frozen in Qatar and in some foreign banks. A U.S. official denied this, saying Washington had not agreed to release those assets.

According to Iranian state television and officials, beyond seeking the release of frozen assets abroad, Tehran also wants control of the Hormuz Strait, compensation for war damages, and a ceasefire across the region, including Lebanon. Iran also wants to levy transit fees on ships passing through the strait.

Impact: Oil markets and the broader regional ceasefire

The more-than-six-week conflict has driven global crude prices higher, increasing concerns about potential negative effects on the world economy.

Israel, a U.S. ally, continues to strike Hezbollah forces backed by Iran in Lebanon, arguing that the Lebanon front is not within the ceasefire’s scope. Tehran says fighting in Lebanon must also end.

Analysis and next steps

Analysts said that while Trump’s public stance has sometimes shifted, Washington’s core objective appears to be reopening the Hormuz Strait for international shipping and preventing Iran from developing capabilities that could lead to a nuclear weapon. Tehran has long rejected these allegations.

After the talks ended, Pakistan’s Foreign Minister Ishaq Dar said the “essential thing now is that all sides continue to observe the ceasefire,” and said Islamabad would work to push the next round of talks between Iran and the United States in coming days.