A Sikh prison inmate is suing a county in California for violating his religious rights by refusing to allow him to wear a turban.
Sikh men must cover their heads at all times
Harpal Singh Cheema, a Sikh activist and human rights lawyer, has been held in jail since 1997 awaiting a decision on his asylum application.
The American Civil Liberties Union, which is backing the case, says Mr Cheema feels "debased and defiled".
Sikh men are required by their faith to cover their heads at all times.
Mr Cheema has been detained for eight years. Since 2002 he has been an inmate of Marysville prison, north of the state capital, Sacramento.
The ACLU is bringing the case against Yuba County, naming the county sheriff, jail officials and the immigration and Customs department.
The lawsuit says Mr Cheema should be allowed to wear the turban "subject to reasonable security requirements".
The inmate has reportedly been refused permission to wear his turban other than in bed.
ACLU counsellor Robin Goldfaden said: "It is deeply troubling that a person seeking refuge from persecution can not only be locked up for years on end but also be deprived of the religious freedom he expected in America."
He added: "Confinement to bed should not be the price of complying with religious obligations."
The lawsuit, which also seeks monetary compensation, is being brought under religious freedom acts and rights specified in the First Amendment.
Jaskaran Kaur, of rights watchdog Ensaaf, said: "Wearing a turban is one of the Sikh religion's central requirements. For Mr Cheema, having his head uncovered is a deeply humiliating and defiling experience."
Virginia Kice, spokeswoman for the immigration department, told Associated Press it made "every effort to accommodate the religious needs of those who are in our custody".
In April last year, a US judge ruled a Sikh traffic policeman in New York, who was forced to leave his job because he insisted on wearing a turban, should be reinstated.