HONG KONG — Phan Van Khai, a Soviet-trained Vietnamese prime minister who helped his country transition away from a state-dominated economy and build a stronger relationship with the United States, died last Saturday in Ho Chi Minh City. He was 84.

Mr. Khai’s death was widely reported this week in Vietnam’s state-controlled news media. Nhan Dan, the official newspaper of the country’s governing Communist Party, reported that the cause was old age.

Mr. Khai, who served as prime minister from 1997 to 2006, had more formal training in economics than previous prime ministers, but also “a practical knowledge that was closely linked to the economic life of the people,” said Le Dang Doanh, one of his former economic advisers.

Among other accomplishments, Mr. Khai helped Vietnam weather the impacts of the Asian financial crisis of 1997-1998, Dr. Doanh said. He also endorsed a landmark 1999 law that made it easier for ordinary people to open businesses, Dr. Doanh added, and played a central role in negotiating Vietnam’s 2007 entry into the World Trade Organization.