The death toll from an earthquake that devastated a remote region of China has killed 615 people, state media said Thursday, as hopes of finding any more survivors faded.

Rescue efforts in the southwestern province of Yunnan, where the 6.1-magnitude quake struck Sunday, were heavily hampered by traffic delays and landslides blocking roads.

At least 615 people had been confirmed killed as of Thursday morning, state broadcaster China Central Television (CCTV) cited officials as saying.

It added that 3,143 people were injured and at least 230,000 had been evacuated, while more than 80,000 homes had fully or partially collapsed.

In one tale of good news from the disaster zone, rescuers freed a 50-year-old female survivor from underneath a pile of rubble on Wednesday afternoon, where she had been trapped for almost three days.

Liao Tengcui was conscious at the time of her rescue, although she had suffered from "serious injuries" and was unable to move her left leg, the official Xinhua news agency reported.

But four days after the tremor, any hopes that survivors remained under wreckage were slim.

No explanation was given for the increase in the death toll, though rescuers have been steadily pulling corpses from the ruins of collapsed buildings.