The Panama-registered Sanchi tanker sank Sunday after an explosion rocked it and sent flames shooting up, CCTV reported.

Chinese maritime authorities launched a search and rescue operation for the 30 Iranian and two Bangladeshi crew onboard the Sanchi. China's Ministry of Transport said the 21 Chinese sailors from the CF-Crystal had been rescued.

Iran joined the international rescue effort led by China, sending a rescue team of its own, including Iranian navy commandos on speed boats. But the teams couldn't get close to the burning tanker due to the heat.

Three bodies were recovered over the week and just hours before the Sanchi's sinking Sunday. Iran announced that all the ship's crew members were presumed dead, according to Iranian state media.