Iran is preparing a counter-proposal after rejecting the U.S. nuclear deal, prompting President Trump to caution that "time is running out."

President Vladimir Putin told U.S. President Donald Trump that he was ready to use Russia's close partnership with Iran to help with negotiations over Iran's nuclear programme, the Kremlin said on Thursday.

Iran’s supreme leader effectively rejected a U.S. proposal that allows temporary uranium enrichment in the country before ending it completely, forcing the White House to reconsider its approach as tensions mount over Iran’s nuclear program.