Rescue workers drill the third manhole on the bottom of the overturned Eastern Star cruise ship in the Jianli section of Yangtze River, central China's Hubei Province, to search for survivors on June 3, 2015. [Photo: Xinhua]

Rescue workers have drilled 3 manholes on the bottom of the overturned Eastern Star cruise ship in the Yangtze River to search for any survivors.

Earlier, two manholes were drilled and later sealed after no survivors were found.

According to experts, the manholes' drilling to search for survivors will have to be completed within the 72-hour 'golden period', which is regarded as the most precious period to save lives.

If there are still no survivors found after the 'golden period', the overturned ship will be righted.