Trump has no plans to meet Iran's 'lovely' Rouhani

US President Donald Trump on Tuesday said he has no plans to meet with Iranian President Hassan Rouhani, ahead of what is expected to be a tense encounter between the two at the UN General Assembly in New York.

Speaking on Twitter, Trump left the door open for a possible meeting in the future.

"Despite requests, I have no plans to meet Iranian President Hassan Rouhani. Maybe someday in the future. I am sure he is an absolutely lovely man," Trump wrote the tweet.

Both Trump and Rouhani are set to take the podium on the opening day of the General Assembly debate on Tuesday, following months of antagonism and exchanges between Tehran and Washington.

The expected showdown in New York will come just four months after Trump decided to ditch the landmark nuclear 2015 nuclear deal, which provided Iran sanctions relief in exchange for agreeing to inspections and limits on nuclear activity.

On Monday, the  five remaining parties to the agreement -Britain, China, France, Germany and Russia - announced plans to keep business ties alive with Iran.

In his address, Rouhani will stress that Iran continues to stick to the 2015 accord and portray the United States as a pariah for breaking its international commitments.

Trump used his UN address last year to bash the nuclear deal as "an embarrassment", signaling that the United States was ready to walk away from the agreement.

After its exit, the United States maintains that it is seeking to ramp up pressure on Iran which it accuses of sowing chaos in Iraq, Syria, Yemen and Lebanon.

"As I have said repeatedly, regime change in Iran is not the administration's policy," Trump's national security adviser John Bolton told reporters.

"We've imposed very stringent sanctions on Iran, more are coming, and what we expect from Iran is massive changes in their behavior," he said.

After a late meeting on Monday, EU foreign policy chief Federica Mogherini announced that a new legal entity would be set up to preserve oil and other business links with Iran.

"This will mean that EU member-states will set up a legal entity to facilitate legitimate financial transactions with Iran and this will allow European companies to continue to trade with Iran," Mogherini told reporters, flanked by Iranian Foreign Minister Mohammad Javad Zarif.

Rouhani has said he has no plans to meet Trump while in New York during the marathon of meetings and slammed the offer of talks as "not genuine". 

As a precondition for any dialogue, Rouhani said Trump would need to repair the damage done by exiting the nuclear deal. "That bridge must be rebuilt," he told NBC news.