HO CHI MINH CITY, Vietnam — U.S. President George W. Bush toured a bird flu lab Monday and praised Vietnam for its successful battle against the disease, pledging U.S. support and urging Southeast Asia to prepare for a potential pandemic.

Bush arrived at the Pasteur Institute - one of Vietnam's top research institutes for communicable diseases - in southern Ho Chi Minh City to an enthusiastic reception from crowds gathered on the streets.

Curious onlookers cheered and waved to him as his motorcade arrived. Vietnamese flags festooned shops and lamp posts and even a few people held up photos of the president.

It is Bush's first trip to the communist country, which hosted leaders from the 21-member Asia-Pacific Economic Co-operation forum over the weekend in the northern capital, Hanoi.

Bush congratulated health officials on Vietnam's effort to combat bird flu, which earlier killed 42 people in Vietnam, but has not claimed any victims during the past 12 months and has not detected any poultry outbreaks this year.

Vietnam's success is largely credited to a nationwide poultry vaccination campaign and strong political will to root out the virus. Some 100,000 people across the country have been deployed to vaccinate poultry against the disease, and about 45 million birds have been destroyed since late 2003.

"Vietnam is serving as a model of how people ought to react," Bush said, vowing to continue supporting the country's fight against bird flu and HIV/AIDS.

Some 153 people have died of bird flu since it began ravaging Asian poultry in late 2003. In Indonesia, Bush's next stop on his Asian tour, it has killed 56 people, the highest toll in one country.

"The visit was very short, but it was a very significant one because the U.S. government, Vietnamese government, and governments worldwide are very interested in HIV/AIDS and avian influenza control," said institute director Nguyen Thi Kim Tien.

During his trip, Bush has praised co-operation among Southeast Asian nations and the United States on fighting bird flu, but has emphasized that the region must not relax its efforts to prevent future outbreaks and prepare for a pandemic.

So far, the H5N1 virus remains hard for people to catch. Most human cases have been traced to contact with infected birds, but experts fear it could mutate into a form that is easily spread among people, potentially igniting a pandemic.

On Sunday, Pacific Rim leaders endorsed an APEC action plan on fighting bird flu and pandemic preparedness, according to a final statement.