BEIJING, March 30 -- Chinese rescuers expanded their search area in the Indian Ocean for the missing Malaysia Airlines passenger jet on Sunday, from the key search sites designated by Australia.

Chief of the China Maritime Search and Rescue Center He Jianzhong told Xinhua that as of 3 p.m. on Sunday, search efforts have failed to discover any suspected objects linked with the plane, and that the Chinese vessels will expand their search area.

Three Chinese search and rescue vessels and four naval warships are searching for any possible debris in the seas west of Australia, while two other vessels are in the east Indian Ocean continuing their search, he said.

The official added that the center has mobilized 61 merchant ships traveling in seas west of Australia and Indonesia as well as another 20 fishing boats in the central Indian Ocean, but nothing has been discovered.

Strong gales are forecast in the next three days with big waves and low visibility in the search site west of Australia, the center said.