Iranian President Ebrahim Raisi told gas exporters in Qatar on Tuesday to avoid any "cruel" sanctions such as those imposed by the United States on Tehran.

Meanwhile, the spokesman of his government said any revival of Iran's 2015 nuclear accord with world powers must lift US sanctions.

"The members of this forum should not recognize those sanctions...(because) in today's world we see that the sanctions are not going to be effective," Raisi said in a gas exporters gathering.

Reuters reported last week that a US-Iranian deal is taking shape in Vienna after months of indirect talks to revive the nuclear pact abandoned in 2018 by then-US President Donald Trump, who also reimposed extensive sanctions on Iran.

"Any sanctions that ... deal a blow to Iran's economic benefits from the (nuclear) deal must be lifted," cabinet spokesman Ali Bahadori Jahromi told a news briefing carried live on a state-run website.

Since 2019, Tehran has gone well beyond the deal's limits, rebuilding stockpiles of enriched uranium, refining it to higher fissile purity and installing advanced centrifuges to speed up output.

Iran had demanded legal assurances that the United States will not exit the deal again, but Washington says it is impossible for US President Joe Biden to provide them.

A draft text of the agreement also alluded to other issues, including unfreezing billions of dollars in Iranian funds in South Korean banks, and the release of Western prisoners held in Iran.

Reporting by Reuters