A letter U.S. President Donald Trump wrote to Iran’s supreme leader in an attempt to jump-start talks over Tehran’s rapidly advancing nuclear program has arrived in the Iranian capital.

The Kremlin, asked on Monday if Russia had held consultations with Iran before or after Tehran responded to a letter from U.S. President Donald Trump urging the country to negotiate a nuclear deal, said Iran formulates its own policy positions.

Iran’s supreme leader, Ayatollah Ali Khamenei, condemned the “bullying tactics” a day after US President Donald Trump threatened military action against the country. According to AFP, Trump threatened military action if Iran refused to engage in talks over its nuclear programme,