American-born Taliban fighter John Walker Lindh will have an August trial on his lawsuit seeking permission to hold daily group prayers in a highly restricted cell block at a federal prison in Terre Haute, Ind.

Lindh, 31, claims the prison's policy restricting group prayer in the unit where he's held violates his religious rights. The government contends the restrictions are necessary for security and don't violate inmates' rights. Muslim inmates can hear each other when they pray individually in their cells, it says.

The lawsuit was originally filed in 2009 by two Muslim inmates in the Communications Management Unit, a special unit that holds mostly Muslim inmates whose communications with the outside world are restricted. Lindh, who is serving a 20-year sentence, joined the lawsuit in 2010. The other plaintiffs have dropped out since then as they were released from prison or transferred to other units.

Muslims are required to pray five times a day, and the Hanbali school to which Lindh belongs requires group prayer if it is possible. But inmates in the CMU are allowed to pray as a group just one hour a week.

The American Civil Liberties Union, which represents Lindh, contends that violates a federal law barring the government from restricting religious activities without showing a compelling need.

U.S. District Judge Jane Magnus-Stinson found in February that daily group prayers were part of Lindh's sincere religious beliefs, but that there were still questions regarding whether the prayer ban is necessary for prison security.

She will hear the case beginning Aug. 27. The site for the trial hasn't been determined.

ACLU legal director Ken Falk and the U.S. attorney's office declined to comment on the case Tuesday. The Bureau of Prisons did not return phone calls and emails seeking comment.

Lindh has modified his request since joining the lawsuit and now seeks permission only to pray in a group three times a day.

In 2002, Lindh pleaded guilty to supplying services to the now-defunct Taliban government and carrying explosives for them. He had been charged with conspiring to kill Americans and support terrorists, but those charges were dropped in a plea agreement. He was transferred to the Terre Haute prison in 2007.