KUALA LUMPUR, March 9 -- The whereabouts of a missing Beijing-bound Malaysia Airline jetliner carrying 227 passengers and 12 crew are still unknown over 30 hours since it was last contacted despite a round-the-clock multilateral search and rescue operation.

The vanished Boeing 777-200ER was presumed to crashed off the Vietnamese coast on Saturday about an hour after it took off from Kuala Lumpur for Beijing.

Director General of the Department of Civil Aviation Malaysia Azharuddin Abdul Rahman told a press conference Sunday morning that the search area has been expanded but still the rescue team is not able to locate anything.

"As also mentioned last night, we have expanded our area of operations, which includes the west side of Malaysian Peninsula," he said.

The official added that the plane lost contact with the ground at 1:30 a.m. local time Saturday while flying over the South China Sea. "There was no sign of abnormalities on the aircraft."

Three aircraft have been dispatched to assist in the search operation, but so far there was no report of any sightings, said the official.

In its latest statement, Malaysia Airlines said it is "doing its utmost to provide support to the affected family members, this includes immediate financial aid."

The company said it would establish a command center at Kota Bharu, Malaysia, or Ho Chi Minh, Vietnam, as soon as the aircraft is located.

Till Sunday noon, no confirmed signs of the plane or any wreckage were detected well over 30 hours after it went missing.

The closest things to clues in the search for the missing plane are two suspicious oil slicks spotted in the Gulf of Thailand at 5: 20 p.m. (1030 GMT) Saturday. One of oil slicks was seen about 150 km from Tho Chu island and the other 190 km from Ca Mau Cape, according to Vietnamese Deputy Transport Minister Pham Quy Tieu.

A international search and rescue mission from Malaysia, China, Singapore, Vietnam, the Philippines, Thailand and the United States had been mobilized with the sea mission. Search operations continued overnight and air mission resumed at daylight Sunday.

Flight MH370, a Boeing B777-200 aircraft carrying 239 people, departed Kuala Lumpur at 0:41 a.m. (1641 GMT) Saturday and was due to land in Beijing at 6:30 a.m.(2230 GMT). Twelve crew members and 227 passengers were on the flight, including 154 Chinese and 38 Malaysians.

Chinese President Xi Jinping has ordered that all-out efforts be made to help search and rescue the missing aircraft. Two warships of the Chinese navy, "Jinggangshan" and "Mianyang", are already on their way to the sea area where the jet is suspected to have crashed.

Two low-flying aircraft of Vietnam's Ministry of Defense also started to head for the sea to search for the vanished plane early Sunday morning.