US President Donald Trump has said a second round of talks between the United States and Iran could resume within days.

In a phone call with The New York Post, Trump said a second round of talks with Iran “could be happening over next two days.”

He initially indicated the discussions would likely take place somewhere in Europe, but later said they could instead be held in Pakistan’s capital, Islamabad, reports AP.

An initial round of negotiations ended without any agreement on Iran’s nuclear ambitions, which the White House has identified as a key sticking point.

UN Secretary-General António Guterres has said it is “highly probable” that US-Iran negotiations will restart.

He made the remarks after meeting Pakistan’s deputy prime minister and foreign minister on Tuesday, praising Islamabad’s efforts to promote peace in the Middle East.

Guterres expressed “enormous admiration” for Pakistan’s initiative and stressed the importance of continued dialogue.

“I consider it essential that these negotiations go on,” Guterres told UN reporters, noting it would be “unrealistic” for long-standing and complex issues between the US and Iran to be resolved in a single round of talks.

“We need negotiations to go on, and we need a ceasefire to persist as negotiations go on,” the secretary-general said.