Passengers' and their nationalities: Chinese 154? Malaysia 38 India 5 Indonesia 7 Australia 6 France 4 USA 3? New Zealand 2 Ukraine?2 Canada 2 Russia 1 Italy 1 Netherlands 1 Austria 1

The investigation into missing Malaysia Airlines flight 370 has entered into new phase with the search area significantly expanded and passengers’ backgrounds still being checked, top Malaysian officials have said.

Malaysia’s Acting Transportation Minister Hishammuddin Hussein said at a press conference on Sunday that the search was now focused areas of shallow water, "large tracts of land, crossing 11 countries, as well as deep and remote oceans".

The number of countries involved in the search has now increased from 14 to 25, the minister said.

Hussein added that the two pilots, suspected by US intelligence analysts of being linked to the disappearance of the passenger plane, had not asked to fly together, giving no more details. (China Daily reporter visited homes of pilots )

He also said the plane’s Aircraft Communications Addressing and Reporting System (ACARS) had been disabled before last radio contact between the plane and air traffic controllers.

Malaysian investigators are still waiting for some countries to send background checks on passengers who were on the flight.

"There are still a few countries yet to respond to our requests," Abu Bakar told the news conference, adding that a deliberate diversion of the plane had not been ruled out.

He said police are also investigating airport ground staff and have intensified their checks on the two pilots, including examining a flight simulator found at the captain's home

	Video: How can an airplane disappear? MH370 is not the first aircraft that has disappeared without a trace.
	Video: Officials remain puzzled Tension mounted as the search for the missing Malaysian airplane continued.