China and Russia are both permanent members of the U.N. Security Council, along with France and Britain, that took part in the original 2015 Iran nuclear deal preliminary framework agreement. Trump withdrew America from the accord in 2018, setting in motion years of tensions in the wider Middle East.

Senior Chinese and Russian diplomats said dialogue should only resume based on "mutual respect" and all sanctions ought to be lifted.

TEHRAN, Iran -- China, Iran and Russia conducted joint naval drills Tuesday in the Middle East, offering a show of force in a region still uneasy over Tehran's rapidly expanding nuclear program and as Yemen's Houthi rebels threaten new attacks on ships.