The two nations will open an institute in Can Tho, the largest city in Vietnam's Mekong Delta, a densely populated, low-lying region with an extensive network of canals and rivers.

The center at Can Tho University will be used by scientists to share information and data that will help them understand the threats to the world's largest river deltas, said Gregory Smith, a scientist with the US Department of the Interior.

With millions of people living along its long coast and across the Mekong Delta, Vietnam is considered one of the five countries most vulnerable to the potential effects of climate change, said Tran Thuc, director of the country's Institute of Meteorology, Hydrology and Environment.

"If the sea level rises one meter (three feet), the whole Mekong Delta will be submerged," Thuc said.

Smith told a joint news conference that the US hopes to learn lessons that it could apply in the Mississippi River delta, where terrible floods were unleashed in the aftermath of Hurricane Katrina.

"Our interest first and foremost is to build a resilient Mississippi Delta," he said.

To achieve such goals, he said, scientists around the world need to gain a better understanding of how to manage a wide range of human activities in delta areas, including housing, fishing, levees, dams and energy resources.

Smith said the new center in the Mekong, to be called the Dragon

Institute, will be the first of several around the world.

The 15,500-square mile (40,000-square kilometer) Mekong Delta region is home to 17.3m people living in 13 provinces and cities. It produces 90% of Vietnam's rice exports and accounts for 60% of its fish and seafood exports, according to the United Nations Development Program.