BEIJING (AP) — Rescue ships looking for 31 missing crew members from a burning oil tanker have expanded their search area to more than 2,600 square kilometers (1,000 square miles).

The expanded search comes six days after the Iranian-owned Sanchi collided with a freighter in the East China Sea and burst into flames.

Chinese state television cited officials at the scene in reporting Friday that authorities still have not found any survivors or put out the blaze on the Sanchi. One body has been recovered.

Twelve ships spraying foam are struggling to extinguish the tanker, which was carrying a cargo of nearly 1 million barrels of condensate, a type of gassy, ultra-light oil.

Search and firefighting efforts resumed Thursday after an onboard explosion rocked the tanker Wednesday. Chinese authorities fear it could explode.