Vietnam, Malaysia and China among other countries have sent forces to search for the plane with 239 people onboard.

　　Flight MH370, carrying 12 crew members and 227 passengers, including 154 Chinese, operated by Malaysia Airlines' Boeing 777- 200 left Kuala Lumpur International Airport for Beijing lost contact with air traffic control on Saturday when it was flying over the Ho Chi Minh air traffic control area.

　　"The multinational search and rescue operation has involved forces from sea, air to land, working around the clock with searching scope expanding," Chinese ambassador to Vietnam Kong Xuanyou said during an interview in Vietnam's capital Hanoi on Tuesday.

　　"The coordination among countries in such incident is very important to ensure that the operation would proceed smoothly and effectively," the ambassador said.

　　Vietnam has widened the search for the missing Malaysian jetliner to the further east and west of the Gulf of Thailand. Meanwhile its joint operation with Malaysia near the Strait of Malacca has so far made little progress, according to Do Minh Tuan, deputy commander of the air force at a press conference held in Phu Quoc Tuesday.

　　Tuan said the search effort would continue and probably at a bigger scope, and that no time limit would be set.

　　Tuan told reporters that no suspected debris or other objects from the missing aircraft had been found and some of the objects found earlier were later dismissed as irrelevant to the jetliner after lab tests. These included the white floating objects reported by the Americans, which turned out to have nothing to do with the missing air plane.

　　The air force commander said the Vietnamese authorities had not only called its navy and air forces into action, but also enlisted local fishermen in the efforts, and asked them to report to authorities once any suspicious objects were sighted during the search.

　　Vietnam has sent 10 sorties of aircraft into this major search operation and planned to ask China to send two more aircraft as reinforcement, he said.

　　Regarding Vietnamese government's response to the incident, Vietnamese Prime Minister earlier on Sunday ordered its entire search and rescue team to work around the clock to search for the missing Malaysian airplane.

　　The country also established a command post on Phu Quoc Island for timely steering, monitoring and directing the search and rescue operation.

　　Vietnamese Deputy Transport Minister Pham Quy Tieu, who is also chief coordinator of the Phu Quoc command post, said the country is ready to coordinate with search and rescue forces from other countries to work out the best plan to hunt for the missing plane.

　　Vietnam is ready to facilitate international ships to enter its waters to search for the airplane, however, the operation of all vessels must be under strict management, said Do Ba Ty, chief of the general staff of Vietnam People's Army and deputy defense minister.

　　Vietnam will divide aerial space for aircraft, meanwhile, it will navigate foreign vessels to search in specific areas.

　　As of Monday, Vietnam has licensed 34 aircraft and 40 vessels from several countries to enter its waters for search mission.

　　The country has allowed U.S. Navy's destroyer USS Pinckney carrying two MH-60R helicopters and one P-3C Orion aircraft to join the searching work.

　　The U.S. Navy said Monday it has dispatched one more Arleigh Burke-class guided-missile destroyer, USS Kidd, to join the USS Pinckney in the search efforts.

　　Other countries, including Thailand and New Zealand, also sent search and rescue missions to the targeted sea area.

　　A Thai navy boat was searching the lower part of the Andaman Sea off southern Thailand, while a New Zealand air force P3 Orion aircraft is en route to join the search.

　　According to China's marine search and rescue center, so far, five Chinese vessels have arrived at the waters around Flight MH370's last known location. Three more vessels are scheduled to get to the searching area later on Wednesday.

　　Vietnam Tuesday decided to expand searching work for the missing Malaysian jet to inland area, along the two flight routes, from Ca Mau's Hon Khoai to Ho Chi Minh City, and provinces in southwest, southeast and south central area of Vietnam.

　　Vo Van Tuan, deputy chief of staff of the Vietnamese army said the country will deploy forces in land, at mountainous and forest areas, as well as coordinate with Cambodia and Laos to search their border areas.

　　Earlier on Monday, Malaysia said tests on a sample of the oil slicks found off the eastern Malaysia coast revealed that it was not from the missing flight, and the two passengers on board with false European passports, an Austrian and an Italian one, are not with Asian appearance.

　　"Given the current situation, how to strengthen consultation, coordination, as well as how to divide searching areas among all parties are very important. There could be a platform for consultation and real-time communication among all relevant parties to work for the best effects," Kong Xuan You, Chinese ambassador to Vietnam said.