Officials in Vietnam have said that rescue planes searching for a missing Malaysia Airlines plane that vanished from radar screens over the South China Sea have spotted oil slicks.
There were no reports of bad weather and no sign why the Boeing 777-200 ER, powered by Rolls-Royce Trent engines, would have vanished from radar screens about an hour after take-off.
The plane had 227 passengers and 12 crew on board when it went missing.
Beijing-bound flight MH370 last made contact with air traffic controllers 120 nautical miles off the east coast Malaysian town of Kota Bharu, the airline's top official said.
A large number of planes and ships from several countries were scouring the area where the plane last made contact, about halfway between Malaysia and the southern tip of Vietnam.
"The search and rescue operations will continue as long as necessary," Malaysian Prime Minister Najib Razak told reporters in Kuala Lumpur.
He said 15 air force aircraft, six navy ships and three coast guard vessels had been pressed into service by Malaysia.
China, and the Philippines have sent ships to the region to help.
The United States, the Philippines, and Singapore also dispatched military planes to help in the search.
The flight left Kuala Lumpur at 12.21am (4.21pm Irish time Friday) but no trace had been found of the plane hours after it was due to land in the Chinese capital at 6.30am (10.30pm Friday) the same day.
There have been no indications of sabotage or claims of a terrorist attack.
Malaysia Airlines said people from 14 nationalities were among the 227 passengers, including at least 152 Chinese, 38 Malaysians, 12 Indonesians, six Australians and three Americans.
It also said a Chinese infant and an American infant were on board.
Italy’s Foreign Ministry said no Italian was on board the despite an Italian citizen being included on the passenger list.
The passenger list provided by the company includes Luigi Maraldi, 37, an Italian citizen.
Newspaper Corriere Della Sera reported that Mr Maraldi's passport was stolen in Thailand last August.
The Italian Interior Ministry was unable to immediately comment on the report.
Meanwhile, Austria’s Foreign Ministry said an Austrian citizen reported to have been on the flight is safe in Austria. Their passport had been reported stolen.
Flight tracking website flightaware.com showed the plane flew northeast over Malaysia after takeoff and climbed to an altitude of 35,000 feet.
The flight vanished from the website's tracking records a minute later while it was still climbing.
The plane, aged over 11 years, disappeared without giving a distress signal - a chilling echo of an Air France flight that crashed into the South Atlantic on 1 June 2009, killing all 228 people on board.
It vanished for hours and wreckage was found only two days later.
If it is confirmed that Malaysia Airlines plane has crashed, the loss would mark the second fatal accident involving a Boeing 777 in less than a year and by far the worst since the jet entered service in 1995.
An Asiana Airlines Boeing 777-200 ER crash-landed in San Francisco in July 2013, killing three passengers and injuring more than 180.
Boeing said it was aware of reports that the Malaysia Airlines plane was missing and was monitoring the situation but had no further comment.
The flight was operating as a China Southern Airlines code share.
An official at the Civil Aviation Authority of Vietnam (CAAV) said the plane had failed to check in as scheduled while it was flying over the sea between Malaysia and Ho Chi Minh city.