By Steve Holland, Humeyra Pamuk, Tala Ramadan and Elwely Elwelly
WASHINGTON/DUBAI, April 15 (Reuters) - The Trump administration expressed optimism on Wednesday about reaching a deal to end the war with Iran, while also warning of increasing economic pressure against Tehran if it remains defiant.
President Donald Trump has said he believes the war he launched with Israel in late February is nearly over, even as a shipping blockade he announced came into effect and traffic through the Strait of Hormuz remained well below normal levels.
The U.S. warned it could add secondary sanctions on buyers of Iranian oil in an apparent effort to gain leverage ahead of more negotiations, just weeks after Washington loosened the enforcement of some Iran energy sanctions.
U.S. and Iranian officials were weighing a return to Pakistan for further talks as early as the coming weekend, after negotiations ended on Sunday without a breakthrough. Mediator Pakistan's army chief arrived in Tehran on Wednesday to try to prevent a renewal of the conflict.
"We feel good about the prospects of a deal," White House press secretary Karoline Leavitt said at a news conference, calling conversations mediated by Pakistan "productive and ongoing." She denied reports that the U.S. had formally requested an extension of a two-week ceasefire agreed by the two sides on April 8.
More in-person talks had not yet been confirmed but would likely take place in Pakistan again, Leavitt said.
Pakistan's military confirmed Field Marshal Asim Munir had arrived in Tehran. A senior Iranian source told Reuters that Munir, who had mediated the last round of talks, would seek "to narrow gaps" between the two sides. Foreign Minister Abbas Araqchi posted on X welcoming Munir and said Iran was committed to "promoting peace and stability in the region."
The talks last weekend broke down without an agreement to end the war, which Trump began alongside Israel on February 28, triggering Iranian attacks on Iran's Gulf neighbours and reigniting a conflict between Israel and Iran-backed Hezbollah in Lebanon.
ECONOMIC PRESSURE ON IRAN
Treasury Secretary Scott Bessent, speaking alongside Leavitt, predicted that China's purchase of Iranian oil would "pause" given the U.S. blockade on vessels calling at Iranian ports. He said the U.S. could impose secondary sanctions on countries that purchase Iranian crude.
The U.S. Treasury had warned two Chinese banks not to process Iranian money or face sanctions, he said, without naming the banks. China previously bought more than 80% of Iran's shipped oil.
"The Iranians should know that this is going to be the financial equivalent of what we saw in the kinetic activities," Bessent said, referring to the U.S. and Israeli campaign of airstrikes that killed a number of Iranian leaders and damaged its defensive capacities and navy.
He also said the U.S. would not renew waivers that allowed the purchase of some Russian and Iranian oil without facing U.S. sanctions. The moves signal an end to the Trump administration's efforts to use the waivers to free up more oil supplies and lower soaring global energy prices.
The war has led Iran to effectively shut the Strait of Hormuz - a vital artery for global crude and gas shipments - to ships other than its own, sharply reducing exports from the Gulf and leaving energy importers scrambling for alternative supplies.
Iran could consider allowing ships to sail freely through the Omani side of the strait without risk of attack as part of proposals it has offered in negotiations with the U.S., providing a deal is clinched to prevent renewed conflict, a source briefed by Tehran said.
Finance ministers from almost a dozen countries led by Britain called on the U.S., Israel and Iran to implement their ceasefire in full and said the conflict would weigh on the global economy and markets even if it was resolved soon.
TANKERS INTERCEPTED
During the first 48 hours of the U.S. blockade on ships entering and exiting Iranian ports, no vessels have made it past U.S. forces, the U.S. military said. Additionally, nine vessels complied with direction from U.S. forces to turn around and return toward an Iranian port or coastal area.
However, Iran's Fars News agency said an Iranian supertanker subject to U.S. sanctions crossed the strait towards Iran's Imam Khomeini port despite the blockade. Fars did not identify the tanker or give further details of its voyage.
Iran's joint military command warned it would halt trade flows in the Gulf, the Sea of Oman and the Red Sea - which connects to the Suez Canal - if the U.S. blockade continued.
Trump has also threatened to escalate if the war resumes.
"We could take out every one of their bridges in one hour. We could take out every one of their power plants, electric power plants, in one hour. We don't want to do that...so we'll see what happens," he told Fox Business Network.
TALKS COMPLICATED BY NUCLEAR ISSUE, LEBANON
Iran's nuclear ambitions were a key sticking point at last weekend's talks. The U.S. proposed a 20-year suspension of all nuclear activity by Iran - an apparent concession from longstanding demands for a permanent ban - while Tehran suggested a halt of three to five years, according to people familiar with the proposals.
Washington has also pressed for any enriched nuclear material to be removed from Iran, while Tehran has demanded that international sanctions against it be lifted.
One source involved in the talks said back-channel discussions had made progress in narrowing gaps, bringing the two sides closer to a deal that could be presented at a new round of talks.
Further complicating peace efforts, Israel has continued to attack Lebanon as it targets Iran-backed Hezbollah. Israel and the U.S. say that campaign is not covered by the ceasefire, while Iran insists it is.
Israeli Prime Minister Benjamin Netanyahu said in a video statement on Wednesday evening that Israel was "prepared for any scenario" when it comes to the war with Iran.
(Reporting by Reuters bureaus, Writing by Ros Russell, Keith Weir and Simon Lewis; Editing by Peter Graff, Hugh Lawson and Nia Williams)
