War with Iran: Trump says US officials will head to Pakistan for negotiations

US-Iran talks have made progress, but 'gaps' remain, Tehran's chief negotiator says

Iran's parliament speaker and chief peace negotiator, Mohammad Bagher Ghalibaf, said talks with the United States have made progress, but "many gaps and some fundamental points remain."

Speaking on Iranian state TV in a long address that ran for about an hour, covering the recent talks in Islamabad, Ghalibaf said the two sides had reached agreement on some matters, while others remain unresolved, with new proposals still under discussion.

He said both sides have "one or two" core issues that are non-negotiable, adding that "the distance to a final agreement remains considerable."

Ghalibaf stressed that the United States must take steps to build trust with the Iranian public, calling it "the most important step" in the process.

-ABC News’ Rashid Haddou and Maryam Rahimi

Trump again threatens to strike Iranian infrastructure; announces new round of talks in Islamabad

President Donald Trump said in a Sunday post on his social media platform that he was dispatching his representatives to Islamabad, Pakistan, for another round of peace talks with Iran on Monday night.

"My Representatives are going to Islamabad, Pakistan – They will be there tomorrow evening, for Negotiations," the president wrote.

He also blasted Iran for allegedly firing on vessels transiting the Strait of Hormuz Saturday, which he called a “total violation” of the ceasefire, and urged Iran to make a deal with the U.S. or face strikes on power plants and bridges inside the country.

“We’re offering a very fair and reasonable DEAL, and I hope they take it because, if they don’t, the United States is going to knock out every single Power Plant, and every single Bridge, in Iran. NO MORE MR. NICE GUY!" Trump wrote. "They’ll come down fast, they’ll come down easy and, if they don’t take the DEAL, it will be my Honor to do what has to be done, which should have been done to Iran, by other Presidents, for the last 47 years. IT’S TIME FOR THE IRAN KILLING MACHINE TO END!"

Trump made a similar threat against Iran on Easter weekend, posting on his social media platform that he would bomb Iran's power plants and bridges and send the country "back to the Stone Ages, where they belong" if they didn't then open the Strait of Hormuz to shipping traffic.

The current ceasefire agreement is set to expire on Wednesday.

-ABC News' Nicholas Kerr