Media playback is unsupported on your device Media caption Jonathan Head says there are distressing scenes at Kuala Lumpur airport as relatives wait for news

South-east Asian states have joined forces to search waters between Malaysia and Vietnam after a Malaysia Airlines plane vanished on a flight to Beijing, with 239 people on board.

Malaysia Airlines said in a statement that flight MH370 had disappeared at 02:40 local time on Saturday (18:40 GMT on Friday) after leaving Kuala Lumpur.

It had been expected to land in Beijing at 06:30 (22:30 GMT).

Malaysia's transport minister said there was no information on wreckage.

"We are doing everything in our power to locate the plane," Hishammuddin Hussein told reporters in Kuala Lumpur.

At the scene The relatives and friends waiting to meet passengers from flight MH370 have been taken to the Lido Hotel, a short drive from Beijing Airport's Terminal Three. Some are of course clearly very distressed and volunteers are providing them with support. But there have been complaints, and at least one angry outburst, about the lack of information from the airline. "We've waited for hours and they've told us very few details," one man said. Some of the anger has also been directed at the large group of journalists gathered outside the room in which the relatives have been taken to. "Don't you all have families?" one is reported to have asked. A statement from Malaysian Airlines says it has sent another team of "caregivers and volunteers" from Kuala Lumpur who are expected to arrive in Beijing later tonight. In pictures: Missing Malaysia plane Air disasters timeline

"Our hope is that the people understand we are being as transparent as we can, we are giving information as quickly as we can, but we want to make sure information has been verified."

Malaysia Airlines chief executive Ahmad Jauhari Yahya said the focus was on helping the families of those missing. He said that 80% of the families had been contacted.

The plane went off the radar south of Vietnam, according to a statement on the Vietnamese government website.

Its last known location was off the country's Ca Mau peninsula although the exact position was not clear, it said.

The Boeing B777-200 aircraft was carrying 227 passengers, including seven children, and 12 crew members.

'Very worried'

Malaysia's military said a second wave of helicopters and ships had been despatched after an initial search revealed nothing.

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.

Vietnam also sent aircraft and ships while Vietnamese fishermen in the area were asked to report any suspected sign of the missing plane.

"In times of emergencies like this, we have to show unity of efforts that transcends boundaries and issues," said Lt Gen Roy Deveraturda, commander of the Philippine military's Western Command.

The passengers were of 14 different nationalities, Mr Jauhari said.

Among them were 152 Chinese nationals, 38 Malaysians, 12 people from Indonesia and six from Australia.

Image copyright AP Image caption Relatives gathered at Beijing International Airport fearing the worst

Image copyright AP Image caption They had faced hours of waiting with no news - arrivals boards simply displayed a sign of a flight delay

Image copyright Reuters Image caption Relatives of passengers also waited for news at the plane's departure airport in Kuala Lumpur

Image copyright AP Image caption Malaysia Airlines is the national carrier of Malaysia and one of the largest in Asia

Flight MH370 passengers 153 Chinese including one child

38 Malaysians

12 Indonesians

6 Australians

Four Americans including one child

Three French

Two each from New Zealand, Ukraine and Canada

One each from Russia, Italy, Taiwan, Netherlands and Austria Source: Malaysia Airlines

The pilot was Capt Zaharie Ahmad Shah, 53, who joined Malaysia Airlines in 1981, Mr Yahya said.

A Vietnamese navy official told the BBC the plane had gone missing within Malaysian maritime territory.

Friends and relatives expecting to meet passengers from the flight in Beijing were instructed to go to a nearby hotel where officials were meant to be on hand to provide support.

"They should have told us something before now," a visibly distressed man in his thirties told AFP news agency at the hotel.

My house has become a place of mourning Hamid Ramlan, Malasyian father of a woman aboard the plane

"They are useless," another young man said of the airline. "I don't know why they haven't released any information."

In Kuala Lumpur, Hamid Ramlan, a 56-year-old police officer, said his daughter and son-in-law had been on the flight for an intended holiday in Beijing.

"My wife is crying," he said. "Everyone is sad. My house has become a place of mourning. This is Allah's will. We have to accept it."

The plane had been flying at an altitude of 35,000ft (10,700m) and the pilots had not reported any problems with the aircraft, Fuad Sharuji, Malaysian Airlines' vice-president of operations control, told CNN.

Media playback is unsupported on your device Media caption Air traffic control lost contact with the Malaysia Airlines plane after leaving Kuala Lumpur

Media playback is unsupported on your device Media caption Chinese airports have stepped up security in the wake of the incident, as John Sudworth reports

Boeing 777 fact sheet Twin-engine jet launched in June 1995

One of the world's most popular long-distance planes

Seats between 300 and 380 passengers

Has flown around five million flights

Often used for non-stop flights of 16 hours or more

In September 2001 a crew member died in a re-fuelling fire on a 777 at Denver International Airport

In 2013 three Chinese women died when the 777 Asiana Flight 214 crashed in San Francisco

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

The route between Kuala Lumpur to Beijing has become more and more popular as Malaysia and China increase trade, says the BBC's Jennifer Pak in Kuala Lumpur.

The Boeing 777 had not had a fatal crash in its 20-year history until an Asiana plane came down at San Francisco airport in July of last year. Three teenage girls from China died in that incident.

Boeing said in a statement posted on Twitter: "We're closely monitoring reports on Malaysia flight MH370. Our thoughts are with everyone on board."