Failed talks between Iran and the United States over the weekend dashed hopes of a swift deal to permanently end the war that has killed thousands and thrown the global economy into turmoil since it began in late February.

Russia, which possesses the world's largest stockpile of nuclear weapons, has repeatedly offered to host Iran's enriched uranium as part of any peace deal.

"This proposal was voiced by President Putin in contacts with both the United States and regional states. The offer still stands, but has not been acted upon," the Kremlin's spokesman Dmitry Peskov told reporters on Monday in response to a question by AFP.

The Kremlin also criticised Trump's threat to blockade the Strait of Hormuz, a key waterway that has been at a standstill since the US and Israel began striking Iran in late February.

"Such actions will likely continue to negatively impact the international market," Peskov said.