Trump, on his first visit to the Middle East since returning to the White House, said he spoke about Iran with the leader of Qatar, which maintains relations with both longtime adversaries.

"It's been really an interesting situation. I have a feeling it's going to work out," Trump said of Iran after talks with the emir, Sheikh Tamim bin Hamad Al Thani.

The Trump administration has held four rounds of talks with Tehran, as the president seeks to avert a threatened Israeli military strike on the Iranian nuclear programme.

"I want to make a deal with Iran. I want to do something, if it's possible," Trump told a summit of Gulf Arab leaders in Riyadh earlier Wednesday.

"But for that to happen, it must stop sponsoring terror, halt its bloody proxy wars, and permanently and verifiably cease its pursuit of nuclear weapons.

"I'm strongly urging all nations to join us in fully and totally enforcing the sanctions" imposed on Iran by the United States, he said.

The Trump administration in recent weeks has imposed sanctions on a series of entities and individuals linked to Iran's oil industry and nuclear programme.

- 'Very deceptive view' -

In 2018, Trump walked out of a landmark agreement between major powers and Iran that gave it sanctions relief in return for UN-monitored restrictions on its nuclear activities.

He slapped sweeping sanctions on Iran, including secondary measures against any country that buys Iranian oil.

Trump said that such secondary sanctions "are in certain ways even more devastating" than direct sanctions on Iran.

Trump in a speech Tuesday in Riyadh also said he favoured diplomacy but harshly criticised Iran's clerical leaders, saying they were "focused on stealing their people's wealth to fund terror and bloodshed abroad".

Iranian Foreign Minister Abbas Araghchi said that he had listened to the remarks and "unfortunately a very deceptive view has been put forward".

Iranian officials and the Trump administration have both offered positive takes on the initial talks.

But it is unclear whether they went in depth, including on the key issue of whether the US will insist on ending all Iranian uranium enrichment, including for civilian purposes.

Asked by a reporter on Air Force One whether he was prepared to exert more pressure on Iran, Trump said: "Let's see what happens over the next week."

Iran also said it would hold talks in Turkey on Friday with representatives of Britain, France and Germany.

The three European powers were part of the 2015 agreement ripped up by Trump in his first term.

"While we continue the dialogue with the United States, we are also ready to talk with the Europeans," Araghchi said.

burs-sct/ds/jsa