The BBC's Alice Budisatrijo describes the growing search effort. Photo: BBC

Rescue teams looking for the plane have now widened their search area.

Investigators are also checking CCTV footage of two passengers who are believed to have boarded the plane using stolen passports.

Flight MH370 from Kuala Lumpur to Beijing disappeared south of Vietnam with 239 people on board.

Continue reading the main story

Analysis

Jennifer PakBBC News, Kuala Lumpur

Malaysia Airlines lost contact with flight MH370 for five hours before it confirmed the news. After that, the authorities began to hold regular news briefings but they were cautious about what they revealed. The slow pace of information forced Malaysians to turn to social media first - then ask the authorities to confirm speculation or reports that appeared online.

Among the many questions was how two passengers with fake European passports could have boarded flight MH370.

Over the past four years, I have travelled frequently through the same airport. As a Canadian passport holder I have to scan both index fingers before I enter the country but not when I leave. The biometric system was set up in 2011 to prevent foreigners from repeatedly coming in to work illegally and to curb human trafficking and wildlife smuggling.

Malaysian officials say they are working hard to answer questions. They have reminded people to avoid speculation, but it hasn't reassured distressed family members.

• What we know about Flight MH370

Air and sea rescue teams have been searching an area of the South China Sea south of Vietnam for more than 30 hours.

But Malaysia's civil aviation chief, Azharuddin Abdul Rahman, told a press conference in Kuala Lumpur the search area had been expanded, to include the west coast of Malaysia.

Five passengers booked on the flight did not board, he added. Their luggage was consequently removed.

There are now 40 ships and 34 aircraft from nine different nationalities searching. But no signal has been received from the plane's emergency locator transmitter, Malaysian aviation authorities say.

Air force chief Rodzali Daud said the investigation was now focusing on a recording of radar signals that showed there was a "possibility" the aircraft had turned back from its flight path.

Vietnamese navy ships which reached two oil slicks spotted earlier in the South China Sea found no signs of wreckage.

'Suspect'

Malaysia's Transport Minister, Hishammuddin Hussein, initially said at least four names on the passenger list were "suspect" but later told the BBC there were in fact only two suspect names.

 

Rodzali Daud, Royal Malaysian Air Force: "There is a possibility the aircraft did make a turn back"

The BBC has confirmed that a man falsely using an Italian passport and a man falsely using an Austrian passport purchased tickets at the same time, and were both booked on the same onward flight from Beijing to Europe on Saturday.

Both had purchased their tickets from China Southern Airlines, which shared the flight with Malaysia Airlines, and they had consecutive ticket numbers.

The real owners reportedly had their passports stolen in Thailand in recent years.

Aerial search teams have yet to spot any wreckage

Military ships have been searching the sea south of Vietnam

Developments have been the subject of intense media attention in Beijing

Mr Hussein said international agencies including the FBI had joined the investigation and all angles were being examined.

"Our own intelligence have been activated and, of course, the counterterrorism units... from all the relevant countries have been informed," he said.

"The main thing here for me and for the families concerned is that we find the aircraft."

The passengers on the flight were of 14 different nationalities. Two-thirds were from China, while others were from elsewhere in Asia, North America and Europe.

When he was asked earlier whether terrorism was suspected as a reason for the plane's disappearance, Malaysian Prime Minister Najib Razak said: "We are looking at all possibilities but it is too early to make any conclusive remarks."

The plane vanished at 17:30 GMT Friday (01:30 local time Saturday).

It reportedly went off the radar south of Vietnam.

Malaysian Airlines had previously said it last had contact with air traffic controllers 120 nautical miles off the east coast of the Malaysian town of Kota Bharu.

 

Chinese airports have stepped up security in the wake of the incident, as John Sudworth reports

Distraught relatives and loved ones of those on board are being given assistance at both the arrival and departure airports.

Many have expressed anger at the lack of information.

"I can't understand the airline company. They should have contacted the families first thing," a middle-aged woman told AFP news agency at Beijing airport, after finding out her brother-in-law was on the flight.

"I don't have any news. I'm very worried," she said.

Some relatives said they were still hoping for miracle, reports the BBC's John Sudworth in Beijing.

But many others will have concluded that there is little hope of aircraft being found, our correspondent adds.

The aerial search was suspended overnight but resumed on Sunday morning.

Malaysia and Vietnam have both sent planes and naval vessels to look for the missing flight.

The US is sending the USS Pinckney, an Arleigh Burke-class guided-missile destroyer, which could be in the central search area within three hours.

US transport safety experts are also joining the investigation.

Territorial disputes over the South China Sea were set aside temporarily as China dispatched two maritime rescue ships and the Philippines deployed three air force planes and three navy patrol ships.

Singapore is also involved, while Vietnam sent aircraft and ships and asked fishermen in the area to report any suspected sign of the missing plane.

Texas firm Freescale Semiconductor says 20 of its Malaysian and Chinese employees were on the flight, according to a statement on its website.

Malaysia's national carrier is one of Asia's largest, flying nearly 37,000 passengers daily to some 80 destinations worldwide.

Correspondents say the route between Kuala Lumpur and Beijing has become more and more popular as Malaysia and China increase trade.