Iran's President Hassan Rouhani has issued a message of condolences over the death of sailors on board an Iranian oil tanker that sank after burning for more than a week following a collision in the East China Sea.

The Sanchi Iranian oil tanker, carrying 136,000 tonnes of condensate from Iran to South Korea, caught fire on January 6 after it collided with the CF Crystal, a Hong Kong-registered bulk freighter, about 160 nautical miles (184 km) off China's coast near Shanghai.

Iranian officials said on Sunday that the vessel had completely sunk and available evidence indicated that all crew members had died soon after the collision and a powerful blast.

Thirty two crew members were on board, comprising 30 Iranians and two Bangladeshis. A Chinese salvage team on Saturday recovered two bodies from the tanker. Another body, presumed to be one of the Sanchi's sailors, was found on Monday and brought to Shanghai for identification.

In his message on Sunday, Rouhani called on concerned Iranian officials to prioritize the identification of the bodies of the victims and to alleviate the agony of their bereaved families.

The Iranian president also called on authorities to launch a thorough investigation into the incident and take all the steps needed to prevent the occurrence of similar accidents. He also called for necessary legal follow-ups to ensure the rights of the Iranian nation and the victims' families.

On Saturday, Rouhani held a phone call with the Iranian Minister of Cooperatives, Labor and Social Welfare Ali Rabiei, who is currently in China as the head of an ad hoc committee tasked with following up on the condition of the tanker and its crew.

The Iranian president called for all available resources to be mobilized and all necessary measures to be taken immediately to determine the fate of the oil tanker's crew.

Zarif expresses condolences over Iran tanker crew's death

In a relevant development, Iranian Foreign Minister Mohammad Javad Zarif also issued a message of condolences over the sad incident.

He said all Iranian officials made their utmost efforts over the past week to rescue the brave sailors, but the country finally ended up mourning their loss.

Iran's top diplomat emphasized that the Foreign Ministry staff both in Iran and in overseas missions in the region of the marine mishap had done their best to save the lives of the tanker's crew.

Zarif added that the Foreign Ministry and all the relevant bodies would follow up on the issue through legal channels in order to accurately determine the cause of the incident and to protect the rights of the Iranian nation and bereaved families of the victims.

Iran announces day of mourning over tanker tragedy

In another development, the Iranian Cabinet declared Monday, January 15, as a nationwide day of public mourning over the tanker disaster.

In a statement on Sunday, the Iranian administration conveyed its condolences to the bereaved families of the victims and said the brave sailors lost their lives as they were on a mission in line with the country's goals.