Vietnamese air force planes have spotted two large oil slicks that authorities suspect are from a Malaysian jetliner that went missing early Saturday.
A Vietnamese government statement says the slicks were spotted off the southern tip of Vietnam. The slicks were each between 10 kilometers (6 miles) and 15 kilometers (9 miles) long.
The statement said the slicks were consistent with the kinds that would be left by fuel from a crashed jetliner.
The Malaysia Airlines Boeing 777 disappeared from radar screens with 239 people on board en route to Beijing.
A Malaysia Airlines flight carrying 239 people — including four Americans — lost contact with air traffic control and was missing hours after it was supposed to have landed in Beijing, the airline said Saturday.
The airline told NBC News that a search-and-rescue mission was under way for Flight MH370, a Boeing 777-200, and that relatives of those on board were being notified.
The flight from Kuala Lumpur, carrying 227 passengers from 14 countries — including two infants — and 12 crew members, had been scheduled to land at 6:30 a.m. in Beijing (5:30 p.m. ET Friday). But Subang Air Traffic Control in Malaysia reported that it lost contact at 2:40 a.m. (1:40 p.m. ET Friday).
In a statement on the official Vietnamese government website, the army said contact with the plane was lost one minute before it entered Vietnam's air traffic control jurisdiction.
It still wasn't known where the plane was, the army said.
As unconfirmed rumors swirled, Malaysian Transport Minister Seri Hishammuddin said at a news briefing in Kuala Lumpur that there was still no information on wreckage more than 12 hours after the plane broke contact.
"It is, indeed, a mystery," Andrew Herdman, director-general of the Association of Asia Pacific Airlines, told the BBC on Saturday. "There's no evidence so far of what happened to this aircraft."
Herdman said it was shocking that a jet with such sophisticated communications could simply vanish without some sort of signal.
"It's extremely unusual, indeed," he said — especially given the 777-200's "extraordinary safety record."
Most of the passengers — 153, including one of the infants — were Chinese, the airline said Saturday. The other infant was an American, one of four on the plane, it said. Thirty-eight people were from Malaysia, and 12 were from Indonesia.
Families of the passengers were shepherded into a room behind closed doors at a Beijing hotel.
The airline identified the pilot as Zaharie Ahmad Shah, 53, a 32-year veteran of the airline with 18,365 hours of flight experience. The first officer, Fariq Hamid, 27, joined the airlines in 2007 and had 2,763 hours of flight time.
"Our thoughts and prayers are with all affected passengers and crew and their family members," the airline said.
Hishammuddin Hussein, Malaysia's defense minister and acting transport minister, took to Twitter to say echo the sentiment, saying he was "shocked."
Michael Palmer, a meteorologist for The Weather Channel, said there were no significant weather conditions in the area.
"It's pretty much clear skies" from Kuala Lampur to Vietnam and the rest of Southeast Asia, Palmer said.
The 777-200 is considered one of the safest aircraft in the world. U.S. aviation records show fewer than 60 incidents, most of them minor, since it made its debut in 1995.
The jet's fire-resistant interior and strong seats were credited with limiting casualties in July when another 777-200, this one operated by Asiana Airlines, crashed at the San Francisco airport. Only two of the 307 people aboard were killed.