Former US President Donald Trump criticized current President Joe Biden's policy on Iran's nuclear program in a post on Truth Social on Wednesday.

"IRAN IS RAPIDLY BUILDING A LARGE SCALE ARSENAL OF NUCLEAR WEAPONS," Trump wrote. "Once they have them, which will be soon, all negotiations STOP. That's when our incompetent fool of a President will drop to his knees and beg IRAN for mercy."

"Three years ago, under 'TRUMP,' Iran was BROKE – NO NUCLEAR WEAPONS, OR PROSPECTS. BIDEN HAS MADE THEM RICH, AND HAS NO IDEA WHAT TO DO. They started the attack on Israel and desperately want to become openly involved. 'Death to Israel,' they chant. DON'T LET IRAN HAVE NUCLEAR WEAPONS!" he added.

Recent reports from the International Atomic Energy Agency (IAEA) have indicated that Iran has accelerated its uranium enrichment.

A report last week from the UN atomic energy found that Iran has installed half the advanced uranium-enriching machines it said earlier it would quickly add to its Fordow site but has not yet brought them online.

The IAEA's previous report determined that Iran has started up new cascades of advanced centrifuges and plans to install others in the coming weeks after facing criticism over its nuclear program.

The UN agency released a report at the end of May which found that Iran has further increased its stockpile of uranium enriched to near weapons-grade levels.

When Trump was President, he withdrew the US from the 2015 nuclear agreement signed between Iran and world powers.

The Biden administration sought to return to the deal and held indirect talks with Iran on a return to compliance, but the negotiations reached a stalemate last September, after Iran submitted an unsatisfactory response to a European Union proposal to revive the deal.