By Guy Faulconbridge and Parisa Hafezi

MOSCOW (Reuters) -Russia said on Wednesday it stood ready to remove highly enriched uranium from Iran and convert it into civilian reactor fuel as a potential way to help narrow U.S.-Iranian differences over the Islamic Republic's nuclear programme.

Tehran says it has the right to peaceful nuclear power, but its swiftly-advancing uranium enrichment programme has raised fears in the wider West and across the Gulf that it wants to develop a nuclear weapon.

The United States is trying to broker a deal to get Iran to rein in its nuclear activities, but President Donald Trump said in an interview released on Wednesday he was less confident than a couple of months ago that Iran will agree to halt enrichment.

Last week, the Kremlin said President Vladimir Putin had told Trump in a phone call that he was ready to use Russia's close partnership with Iran to help advance those negotiations.

On Wednesday, Russian Deputy Foreign Minister Sergei Ryabkov, who oversees arms control and U.S. relations, told Russian media that efforts to reach a solution should be redoubled and that Moscow was willing to help in practical ways.

"We are ready to provide assistance to both Washington and Tehran, not only politically, not only in the form of ideas that could be of use in the negotiation process, but also practically: for example, through the export of excess nuclear material produced by Iran and its subsequent adaptation to the production of fuel for reactors," Ryabkov said.

He did not make clear whether the nuclear fuel would then be returned to Iran for use in its civil nuclear energy programme, which Moscow has helped develop.

The United States wants all of Iran's highly enriched uranium (HEU) to be shipped out of the country. Tehran says it should only send out any excess amount above a ceiling that was agreed in a 2015 deal and cannot abandon enrichment altogether.

Kremlin spokesman Dmitry Peskov on Wednesday confirmed Moscow's readiness to accept the uranium.

"Here it is very important to say that if necessary, if the parties deem it necessary, Russia will be ready to provide such services," Peskov told reporters.

Russia, the world's biggest nuclear power, does not want to see Iran acquire nuclear weapons, but believes it has every right to develop its own civilian nuclear programme - as a member of the 1970 global Non-Proliferation Treaty - and that any use of military force against it would be illegal.

Moscow has bought weapons from Iran for its war in Ukraine and signed a 20-year strategic partnership deal with Tehran earlier this year.

During his 2017-2021 term, Trump withdrew the U.S. from a landmark 2015 deal between Iran and world powers, including Russia, that had placed strict limits on Tehran's nuclear activities in exchange for sanctions relief.

After Trump pulled out in 2018 and reimposed tough U.S. economic sanctions, Iran breached and far surpassed the 2015 deal's limits on enrichment, producing stocks far above what the West says is necessary for a civilian energy programme.

(Reporting by Reuters; writing by Guy Faulconbridge; editing by Andrew Osborn and Mark Heinrich)