Vietnamese courts have handed down harsh prison sentences to two dozen people after finding them guilty of terrorism and subversion including a case linked to an exiled group.

A court in Ho Chi Minh City convicted 14 people for a petrol bomb attack at the city's international airport in April and sentenced them to between five and 16 years in prison Wednesday.

The bomb caused a scare but no casualties. It was linked to an exiled group of the defeated South Vietnamese republic.

A court in south-central province of Binh Dinh sentenced nine people to between three to 14 years for attempted subversion and spreading propaganda against the communist state.

Both cases were reported by state-run Thanh Nien newspaper. Court officials were unavailable for comment Thursday.