Iran and the United States have reached an agreement to exchange prisoners, Iranian Foreign Minister Hossein Amirabdollahian told state TV on Sunday, but Washington denied it as a "false" claim by Tehran.

"Regarding the issue of prisoner swaps between Iran and the U.S. we have reached an agreement in the recent days and if everything goes well on the U.S. side, I think we will witness a prisoner exchange in a short period," Amirabdollahian said.

"On our part everything is ready, while the U.S. is currently working on the final technical coordination."

A White House official denied Amirabdollahian's statement about the prisoner swap, but added that the United States was committed to securing the release of Americans held in Iran.

"Claims by Iranian officials that we have reached a deal for the release of the U.S. citizens wrongfully held by Iran are false," a spokesperson for the White House National Security Council said.

A source briefed on the talks said the prisoner exchange is "closer than it has ever been," but one of the remaining sticking points is linked to $7 billion in frozen Iranian oil funds under U.S. sanctions in South Korea.

"The logistics of how these funds will be exchanged and how oversight will be provided are unresolved," said the source, who spoke on the condition of anonymity because of the sensitivity of the negotiations.

The source added that Qatar and Switzerland have been involved in the prisoner exchange talks. Iranian sources told Reuters that two regional countries were involved in the indirect talks between Tehran and Washington.

One of several Americans held in Iran is Siamak Namazi, a businessman with dual U.S.-Iranian citizenship, who was sentenced in 2016 to 10 years in prison for spying and cooperating with the U.S. government.

Emad Sharghi, an Iranian American businessman first arrested in 2018 when he was working for a tech investment company, is also jailed in Iran, as is Iranian American environmentalist Morad Tahbaz, who also holds British citizenship.

For years, Tehran has sought the release of more than a dozen Iranians in the United States, including seven Iranian American dual nationals, two Iranians with permanent U.S. residency and four Iranian citizens with no legal status in the United States. The Islamic Republic, which is holding dozens of Iranian dual nationals and foreigners, has been accused by rights activists of arresting them to try to extract concessions from other countries. Iran has dismissed the charge.

Some Iranian media reported last week that Iran had reached a prisoner swap deal in exchange for the release of the $7 billion in frozen Iranian oil funds.

In 2018, then-U.S. president Donald Trump ditched a 2015 nuclear deal between Iran and six powers and reimposed sanctions that have crippled the Islamic Republic's economy.

The deal had imposed restrictions on Iran's nuclear activities in exchange for lifting international sanctions. In reaction to Washington's sanctions, Tehran has gradually violated curbs of the pact on its nuclear program.

Indirect talks between Tehran and U.S. President Joe Biden's administration on reviving the agreement have stalled since September. The deal imposed restrictions on Iran's nuclear activities in exchange for lifting international sanctions.