"Beyond the military presence (there), we'll have to build peace," Mr Macron said.

Mr Trump earlier warned Iran against resuming its nuclear programme.

"They're not going to be restarting anything. They restart it they're going to have big problems, bigger than they've ever had before."

'Bigger, better' deal

Analysis by the BBC's Barbara Plett Usher

The visit was a strange mix.

On the one hand, a display of stark differences - Mr Macron almost channelling an anti-Trump in his opening admonition to resist "aggressive nationalism" and "build a new multilateralism."

On the other hand, an overt display of deliberate chumminess punctuated with tussling handshakes and capped by the very odd dandruff episode, where Mr Trump seemed to hover between playfulness and aggression.

Meanwhile, Iranian Foreign Minister Javad Zarif said just hours before the Trump-Macron summit that a probable response would to restart the enrichment of uranium - a key bomb-making ingredient.

"You cannot stop the process or not engage just because of a fear of failure. But at least you need to have some hope of success, some prospect for success, in order for this process to start," the Iranian foreign minister was quoted as saying by Reuters.

"And I do not believe that, under the present circumstances, with the present tone, and language and approach of the current administration in Washington, you would have much prospect."

Iran maintains its nuclear programme is solely for peaceful civilian purposes.

What are Trump's objections to the 2015 accord?

The US president has long complained that the accord - signed by the US, Iran, Europe, Russia, China and Germany - does nothing to halt Iran's support for militant groups in the region such as Hezbollah.

Mr Trump is also demanding that signatories to the pact agree permanent restrictions on Iran's uranium enrichment.

• Iran nuclear deal: Key details

Under the current deal they are set to expire in 2025.

What about other issues discussed in Washington?