Russian President Vladimir Putin proposed transporting Iran’s enriched uranium to Russia as part of a potential agreement to end the war in the Middle East during a phone call with US President Donald Trump, Axios reports.

According to the publication, the discussion concerned about 450 kilograms of uranium enriched to 60 percent. Axios notes that such material could be further enriched within several weeks and potentially used to produce more than ten nuclear weapons.

The article also states that the idea had been raised before. According to media reports, Moscow made similar proposals during US-Iran nuclear negotiations in May last year, before the United States and Israel carried out strikes on Iranian nuclear facilities and several weeks before the current war began.

An unnamed US official told the outlet that Trump rejected Putin’s proposal. According to the official, the US position is that the priority should be ensuring the security and control of Iran’s uranium.

Axios also recalled that Russia previously stored Iran’s low-enriched uranium under the 2015 nuclear deal and has the technical capability to receive such material.

Later, Trump declined to comment on reports about Putin’s proposal. When asked whether the Russian president had suggested transferring Iran’s uranium to Russia, he said he could not discuss the matter.