A second round of talks between Iran and the United States, aimed at resolving their dispute over Tehran's nuclear programme, have begun in the Swiss city of Geneva.

The indirect discussions follow repeated military threats against Iran over the country's deadly crackdown on anti-government protests and the ongoing dispute over its nuclear programme.

Speaking to reporters aboard Air Force One ahead of the latest talks, US President Donald Trump said he believed Iran wanted to make a deal over its nuclear programme.

The foreign ministry in Tehran, meanwhile, said it believed that the US position on the nuclear issue had moved towards "a more realistic one".

Iran says Tuesday's meeting, mediated by Oman, will focus on its nuclear programme and the potential lifting of economic sanctions imposed by the US.

Washington has previously indicated it wants to discuss other issues as well, such as Iran's missile stockpile.

Framing the talks as "very important", Trump said he would be "indirectly" involved and suggested Tehran was motivated this time to negotiate.

"I don't think they want the consequences of not making a deal," Trump said, adding that Iran learned the consequences of a tough posture in talks last summer when the US bombed Iranian nuclear sites.

"We could have had a deal instead of sending the B-2s in to knock out their nuclear potential. And we had to send the B-2s," the US president said, referring to the stealth bombers that carried out the bombings. "I hope they're going to be more reasonable."

His threats have come amid a US military build-up in the Middle East over the past few weeks.

BBC Verify has now confirmed the location of US aircraft carrier the USS Abraham Lincoln near Iran using satellite imagery.

The US has also reportedly sent the USS Gerald R Ford, the world's largest warship, to the Middle East, which could arrive in the region within the next three weeks.

In addition to the Abraham Lincoln's arrival, BBC Verify has also tracked an increase of US destroyers, combat ships and fighter jets in the region.

Iran's Foreign Minister Abbas Araqchi met with the UN nuclear watchdog chief on Monday, saying in a post on X he was in Geneva to "achieve a fair and equitable deal".

"What is not on the table: submission before threats," Araqchi said.

Iran has responded to the US build-up with its own show of force. On Monday the Islamic Revolutionary Guard Corps (IRGC) launched a maritime drill in the Strait of Hormuz, located in the Gulf between Oman and Iran.

The Strait is considered a vital international waterway and oil export route from Gulf Arab states.

Washington has dispatched Middle East envoy Steve Witkoff and Trump's son-in-law Jared Kushner, the White House said on Sunday.

Both were involved in indirect talks in the Gulf state of Oman earlier in February, which Araghchi, who led the Iranian delegation, described afterwards as a "good beginning".

US Secretary of State Marco Rubio said on Monday that reaching a deal with Tehran would be "very difficult".

"I think that there's an opportunity here to diplomatically reach an agreement ... but I don't want to overstate it either," Rubio said during a visit to Hungary. "It's going to be hard."