Three Americans and four Vietnamese went on trial on terrorism charges Friday, accused of plotting to take over radio airwaves to call for an uprising against the communist government.

The seven were led into a Ho Chi Minh City courtroom for the one-day trial. If convicted, they face sentences ranging from 12 years in prison to execution.

The defendants, all of Vietnamese descent, have been jailed without charges for more than a year, prompting Washington to pressure Hanoi to move forward swiftly and fairly.

U.S. President George W. Bush and Secretary of State Condoleezza Rice are scheduled to visit Vietnam next week when Hanoi hosts the 21-member Asia-Pacific Economic Cooperation summit — the country's biggest international event ever.

As the trial began, prosecutors read a 21-page indictment accusing the defendants of plotting to smuggle radio equipment to Vietnam with the intent of taking over the airwaves to call for "a total uprising that would lead to violence and harm to the lives of civil servants and ordinary people."

According to the indictment, the scheme was hatched by the "Government of Free Vietnam," a Garden Grove, California, organization that the Vietnamese government considers a terrorist group.

The group is run by Chanh Huu Nguyen, wanted in Vietnam for failed plots to bomb the Vietnamese Embassy in Thailand and targets in Vietnam that included a statue of late communist leader Ho Chi Minh.

"This is a terrorist case of a particularly serious nature with the participation of many people and directed by Chanh, who heads the terrorist organization disguised as The Government of Free Vietnam," the indictment said.

Prosecutors say the group set up an adoption agency in Cambodia as a front to disguise their plans.

On trial are U.S. citizens Thuong Nguyen Foshee, 58, of Orlando, Florida; Le Van Binh, 31, of Tampa, Florida; and Huynh Bich Lien "Linda," 51, of San Gabriel, California.

The Vietnamese citizens on trial are Tran Dat Phuong, 65; brothers Ho Van Giau, 59, and Ho Van Hien, 38, and 35-year-old Cao Tri — a U.S. resident who had been living in St. Petersburg, Florida.

The defendants stood as the indictment was being read. But at one point, Foshee suddenly looked ill and had to sit down. A female police officer fanned her with a piece of paper and patted her on the back while Foshee clenched her hands in her lap.

Under questioning from the judge, some of the defendants acknowledged carrying radio equipment to Cambodia on behalf of the Government of Free Vietnam, while others described themselves as employees of an adoption agency.

Foshee said that Chanh had invited her to join his organization, but that she had declined. She said that she had met with him at his office in the United States several times, and that he had referred to her as "vice foreign minister."

The group gives titles to people as though they served in an actual government.

Foshee's brother, Nguyen Phu Tri, 41, said Vietnamese officials met with him while she was staying at his home in July 2005 during a visit to attend a wedding. He said they told him to warn her to break off any ties with the group.

"I never believed that she was a terrorist," he told The Associated Press.

Tri said Chanh's group gave him an air ticket and money to carry four radio transmitters from the U.S. to Cambodia. He said he had been trained to assemble and operate the equipment so he could pass the knowledge on to others.

Lien said she was not a member of the Government of Free Vietnam, but had gone to work for USIM, a charity in Cambodia that helped arrange adoptions of Cambodian children by people in the United States.

She said that she knew Chanh was associated with USIM, but that all she did was help care for children.

The Government of Free Vietnam is considered among the more virulent of the many anti-communist groups founded by Vietnamese refugees in the United States. Many of its leaders are soldiers of the former South Vietnamese Army who fled Vietnam after the war ended in 1975.

The case has attracted attention from U.S. Sen. Mel Martinez, a Florida Republican, who raised the issue with the administration of President George W. Bush on Foshee's behalf and is reportedly blocking a key vote in Congress that would normalize trade relations between the former foes.