Reports: Jet went down off Vietnam

• NEW: Missing plane crashed off the southern coast of Vietnam, Asian media report


• "We have no idea where this aircraft is," Malaysia Airlines vice president says


• In Beijing, relatives gather in a hotel


• Flight was carrying 239 people, including 2 infants

(CNN) -- A missing Malaysia Airliner carrying 229 people crashed off the southern coast of Vietnam, Vietnamese and Chinese state media reported Saturday, both citing Vietnam's military.

But Malaysia has no information that any wreckage has been found of the missing plane and no confirmation of a crash, acting transport minister Datuk Seri Hishammuddin Hussein told journalists Saturday.

The reports came hours after Malaysia Airlines Flight MH370, traveling from Kuala Lumpur to Beijing, disappeared.

Air traffic controllers lost contact with the aircraft about 2:40 a.m. local time (1:40 p.m. ET Friday), Malaysia Airlines Vice President of Operations Control Fuad Sharuji said on CNN's "AC360."

"At the moment we have no idea where this aircraft is right now," Sharuji said.

Tuoi Tre, a leading daily in Vietnam, reported that the Vietnamese navy confirmed the plane crashed into the ocean. According to navy Adm. Ngo Van Phat, a regional commander, military radar recorded that the plane crashed into the sea south of Phu Quoc island. The People's Daily, Chinese Communist Party's official newspaper, reported the same information.

China deployed two rescue ships to the South China Sea on Saturday as the search intensified, state-run broadcaster CCTV said.

Family and friends of many of the 154 Chinese nationals on board gathered at a hotel complex in the Lido district of Beijing. A large group of reporters gathered outside.

"My son was only 40 years old," one woman wailed as she was led inside. "My son, my son -- what am I going to do?"

The Ministry of Transportation in Malaysia said 80% of family members of those onboard had been contacted.

The Boeing 777-200 departed Kuala Lumpur International Airport at 12:41 a.m. and was expected to land in Beijing at 6:30 a.m., a 2,300-mile (3,700 kilometer) trip. It was carrying 227 passengers, two of them infants, and 12 crew members, the airline said. Air traffic control in Subang, in Malaysia, had last contact with the plane.

If this aircraft has crashed with a total loss, it would the deadliest aviation incident since November 2001 when an American Airlines Airbus A300 crashed in Belle Harbor, Queens, shortly after takeoff from JFK Airport. Killed were 265 people, including five people on the ground.

At the time of its disappearance, Malaysia Airlines Flight MH370 was carrying about 7.5 hours of fuel, Sharuji said.

The passengers are of 13 nationalities, the airline said. Nationalities and the number for each of passengers on the flight were:

-- China and Taiwan,154

-- Malaysia, 38

-- Indonesia, 12

-- Australia, 7

-- United States, 4

-- France, 3

-- New Zealand, 2

-- Ukraine, 2

-- Canada, 2

-- Russia, 1

-- Italy, 1

-- Netherlands, 1

-- Austria, 1

One infant from the United States and another from China were included in the tally.

By CNN's math, that adds up to 228 passengers, one more than the total cited by the airline. There was no immediate explanation offered for the apparent discrepancy.

Malaysia Airlines said it was working with the authorities who have activated their search and rescue team to locate the aircraft. The airline said the public can call +603 7884 1234 for further information.

The airline's website said the flight was piloted by Cap. Zaharie Ahmad Shah, 53, a Malaysian. He has 18,365 total flying hours and joined Malaysia Airlines in 1981, the website said. The first officer is Fariq Ab.Hamid, 27, a Malaysian with a total of 2,763 flying hours. He joined Malaysia Airlines in 2007.

China's state-run Xinhua News Agency said the flight lost contact and its radar signal as it was flying over the Ho Chi Minh air traffic control area in Vietnam.

Chinese Premier Li Keqiang ordered authorities to start emergency measures to strengthen communications with Malaysian authorities, and called for boosting search and rescue efforts as well as verifying details of the Chinese passengers aboard, China's government website reported.

China's embassy in Malaysia has formed an emergency team headed by the Chinese ambassador to deal with the incident, it said.

"We're closely monitoring reports on Malaysia flight MH370," Boeing said in a tweet. "Our thoughts are with everyone on board."

"It doesn't sound very good," retired American Airlines Capt. Jim Tilmon told CNN's "AC360." He noted that the route is mostly overland, which means that there would be plenty of antennae, radar and radios to contact the plane.

"I've been trying to come up with every scenario that I could just to explain this away, but I haven't been very successful."

He said the plane is "about as sophisticated as any commercial airplane could possibly be," with an excellent safety record.

"The lack of communications suggests to me that something most unfortunate has happened," said Mary Schiavo, former inspector general of the U.S. Department of Transportation, in an interview with CNN International. "But that, of course, does not mean that there are not many persons that need to be rescued and secured. There's still a very urgent need to find that plane and to render aid."

There is one recent blemish for the Boeing jet: An Asiana Airlines Boeing 777 carrying 291 passengers struck a seawall at San Francisco International Airport in July 2013, killing three people and wounding dozens more.

Malaysia Airlines operates in Southeast Asia, East Asia, South Asia, the Middle East and on the route between Europe and Australasia.

It has 15 of the Boeing 777-200 planes in its fleet, CNN's Richard Quest reported.

Part of the company is in the private sector, but the government owns most of it.

Malayan Airways Limited began flying in 1937 as an air service between Penang and Singapore. A decade later, it began flying commercially as the national airline.

In 1963, when Malaysia was formed, the airline was renamed Malaysian Airlines Limited.

Within 20 years, it had grown from a single aircraft operator into a company with 2,400 employees and a fleet operator.