Premier Li Keqiang called Malaysia prime minster Najib Razak over the missing plane and urged Malaysian authorities to intensify the search and rescue efforts.
Vietnam already has sent aircraft and marine rescue vessels to search for the missing Malaysian plane.
Singapore has sent a C130 Hercules aircraft for a search and locate mission for the missing plane of Malaysia Airlines (MAS), which carried 239 people.
The Civil Aviation Administration of China has been informed by Vietnamese civil aviation authorities that Vietnam, Malaysia and Singapore are conducting a joint search for a missing Malaysian plane south of Vietnam's Tho Chu Islands.
China, Malaysia, Vietnam, the Philippines, Singapore and Indonesia join search efforts for a plane with 154 Chinese on board. Live Report