HANOI, Vietnam (AP) — A court in Hanoi has handed down harsh sentences against six activists after convicting them of attempting to overthrow Vietnam's government.

Nguyen Van Mieng, the lawyer for prominent human rights lawyer Nguyen Van Dai said he was sentenced to 15 years in prison and five years of house arrest while his fellow activists received sentences from seven to 12 years at the one-day trial Thursday.

They were charged with affiliating with a pro-democracy group called Brotherhood for Democracy, whose purpose was to change the leadership of the Communist Party and build a multi-party system.

A State Department spokeswoman says the United States is deeply troubled with the sentencing and calls for release of all prisoners of conscience immediately.