TEHRAN, Jan. 15 (Xinhua) -- Iran's Supreme Leader Ayatollah Ali Khamenei expressed deep sorrow for the death of crew members on an Iranian oil tanker, Tasnim news agency reported on Monday.

"I extend my sincere condolences to the mourning families and survivors of the Sanchi oil tanker's crew, who passed away during the heartbreaking incident of the burning and sinking tanker," Khamenei said in a statement.

"These beloved ones lost their lives while on duty, serving their country; and this is a great honor that may reduce the weight of grief and soothe the agonizing hearts of their surviving kin," he was quoted as saying.

The crew members, including 30 Iranians and two Bangladeshis, went missing after a Panama-registered oil tanker and a Hong Kong-registered bulk freighter collided on Jan. 6 in waters about 300 kilometers east of the Yangtze River's estuary.

Three bodies have been recovered after Chinese rescuing efforts, with the rest of the crew members still unaccounted for.

The tanker, carrying 136,000 tons of gas condensates and other oils, caught fire after the collision. It sank on Sunday after burning for eight days.

On Sunday, Iran's President Hassan Rouhani also extended his condolences to the families of the dead sailors.

Describing the incident as "tragic" and "heart-breaking," Rouhani said the deaths of the crew have deeply saddened the nation of Iran.

Iran's cabinet has declared Monday, Jan. 15, as a nationwide day of public mourning.