A rabbi hoping to become chaplain to US troops has run into a problem as plain as the hair on his face – his beard.

According to the army’s strict regulations on appearance, anyone serving the military must be clean - shaven, but Chabad rabbi Menachem Stern has a long black beard.

Rabbi Stern was refused a job as a military chaplain last year after he claimed it would contradict his religious beliefs to trim it.

He is now suing the US Army, seeking both the job and damages. His argument is that refusing to emply him because of his religious practice is a violation of his constitutional right.

Rabbi Stern, from New York, has already appealed twice to the beard ban without success but has vowed never to shave his beard off.

The army has previously allowed three Sikh soldiers to keep their turbans and beards despite its policy, while in 1976 a rabbi won a similar case against the US Air Force.

Rabbi Stern said: "By not trimming my beard, I represent the unadulterated view of the holy Torah, the way we believe a person should live.

“I believe this is my calling and mission. I won't give up this fight."

The army is required to respond to the lawsuit within 60 days.