TEHERAN - Iran's Foreign Ministry spokesman Esmaeil Baghaei said on Wednesday the definite date and venue of the fourth round of the indirect nuclear talks between Iran and the United States have not been determined yet.

He made the remarks while responding to a question by the official news agency IRNA regarding the timing and location of the next round of Omani-mediated negotiations on Teheran's nuclear program and the removal of Washington's sanctions.

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Baghaei said Oman would announce the date and venue for the next round once confirmed, noting that Oman had proposed holding the talks in the coming days, a suggestion currently "under review."

Quoting an informed official, Nour News, affiliated with Iran's Supreme National Security Council, said the fourth round of Iran-US talks would be held in the Omani capital Muscat on Sunday.

The upcoming negotiations would focus on humanitarian issues and certain security concerns of both countries, Nour News said.

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The delegations of Iran and the United States have so far held three rounds of talks. The first and third rounds were held in Muscat on April 12 and April 26, and the second one in Rome on April 19.

The fourth round, which was originally scheduled for May 3 in Rome, was postponed due to what Oman described as "logistical reasons."