After briefly scaling down its search and rescue mission for MH370, Vietnam said it is now back in full force and expanding efforts to cover land areas.

Hanoi had embarked on the shocking move earlier due to scanty and confusing information from Malaysia over where the aircraft may have headed after it lost contact with air traffic control.    

China also said its air force would sweep land areas, although it did not specify where.

"We are expanding to the east of the expected route of the flight and on land," Lieutenant General Vo Van Tuan, Vietnam's deputy army chief, was quoted as saying by Reuters.

The confusion over where to look is adding to one of the most baffling mysteries in modern aviation mystery, and prolonging the agonising wait for hundreds of relatives of the

missing passengers and crew.

Adding to the frustration and uncertainty, Malaysia's military has said the plane could have turned around from its planned flight path, but there were conflicting statements and

reports about how far and in which direction it could have flown after communication with the aircraft was lost.

However, air force chief, Rodzali Daud, denied saying military radar had tracked MH370 flying over the Strait of Malacca .

The Boeing 777, which was enroute to Beijing from Kuala Lumpur, has been missing since early Saturday morning.

The plane was carrying 239 people.