A Vietnamese court is to try seven people, including three U.S. citizens, on charges of terrorism. The accused allegedly plotted to hijack Vietnamese radio frequencies to call for an anti-government uprising. 

The People's Court of Ho Chi Minh City says the one-day trial will take place Friday. Until last week, the seven suspects had been imprisoned without charge, some for more than a year.

Prosecutors say they were involved in a 2001 plot to bring FM radio equipment into Vietnam and broadcast calls for an anti-government uprising on the same wavelength as national broadcaster Voice of Vietnam.

Three of those to be tried Friday are naturalized U.S. citizens. The other four are Vietnamese citizens.

Vietnamese government prosecutor Nghiem Quang Xuyen says the accused are charged with terrorism because they are members of a group headed by U.S.-based anti-communist activist Nguyen Huu Chanh. Vietnam considers the group a terrorist organization. The government says Chanh was behind the radio plot.

The Vietnamese government says his group is also responsible for the attempted bombings of several Vietnamese embassies in the late 1990s.

Vietnam expert Carl Thayer of the Australian Defense University says arresting Chanh is a high priority for Vietnam.

"Vietnam has had that organization in its sights since '99. They tried very hard to extradite the alleged leader, Nguyen Huu Chanh, from South Korea this year, and failed," he said.

Vietnam's terrorism law includes a provision that makes it a crime to "intend to oppose the people's administration".

Thayer says Vietnam uses the terrorism card to try to enlist American support against anti-communist organizations.

"Once you had the war on terror, Vietnam has played a game: 'OK, we have terrorists too. And if the United States wants to do business with us, you have got to declare these groups terrorist organizations," added Thayer.

The case has drawn U.S. attention because one of the accused, 58-year-old Cuc Foshee, is a prominent member of the Vietnamese community in Florida, and friends and family have rallied on her behalf.

One U.S. senator has said until Foshee is set free he will block a pending bill to grant Vietnam permanent normal trade relations with the United States.

Vietnam is preparing to host the 21-member Asia-Pacific Economic Cooperation summit next week. U.S. President George Bush is among the world leaders scheduled to attend.