Vietnamese officials say seven political dissidents, including three naturalized U.S. citizens, will be tried on terrorism charges for plotting against the government.

Officials said Thursday a Ho Chi Minh City court will hear the case against the defendants, who the government says used radio broadcasts to incite unrest.

The seven were arrested last year and are accused of taking orders from a pro-democracy activist Hanoi considers a terrorist.

The alleged ringleader, Nguyen Huu Chanh, is a Vietnamese-born citizen of the United States. Three other U.S. residents are part of the group to be tried.

The continued detention of one of the accused - a Vietnamese-born resident of the U.S. state of Florida who was arrested 13 months ago - has blocked improved trade relations between Washington and Hanoi.

Florida Senator Mel Martinez has stalled passage of a bill that would grant Vietnam permanent normal trade relations status because he says Hanoi should release the Florida resident.

Vietnam has been working to strengthen its ties with the U.S. The countries struck a trade deal in May that paves the way for Vietnam to join the World Trade Organization next week.

And U.S. President Bush is due to travel to Hanoi later this month to attend the Asia-Pacific Economic Cooperation summit.

Some information for this report was provided by AP and Reuters.