A photo shows a piece of wreckage of the search plane which has been discovered on June 16, 2016 in the sea near northern Vietnam. [Photo: Xinhua]

Chinese officials have dispatched naval and coast guard vessels to assist in the search for a pair of Vietnamese aircraft which disappeared earlier in the week.

In coordination with Vietnamese officials, the Chinese ships will be focused mostly in Chinese territorial waters in the Beibu Gulf, which is located in between northern Vietnam and Hainan off the southern coast of Guangxi.

At the request of Vietnam, the Maritime Search and Rescue Center in Hainan sent out a pair of search and rescue vessels on Thursday night.

This was followed on Friday by an additional 7 ships from the Chinese Navy and Coast Guard.

A Vietnamese fighter jet, a Russian-built SU-30 with two crews aboard, disappeared on Tuesday, while on a training mission along the northern Vietnamese coast.

On Thursday, a Vietnamese Coast Guard plane with 9 people on-board conducting a search for the missing fighter jet also disappeared.

Wreckage of the search plane has since been discovered.

However, there are still no signs of the fighter jet.