Military chaplains are calling for reassurances that troops will not be punished if they speak out about their opposition to homosexuality.

According to Associated Press, a joint letter from retired chaplains from 21 religious groups to the lead chaplains of the Army, Navy and Air Force says that troops may be unable to speak openly if they fear punishment.

Douglas E Lee, a former military chaplain who signed the letter, said that the lifting of the ban on openly gay soldiers was “already an assault and a challenge on individual conscience and some soldiers may think it’s forcing them to abandon their religious beliefs or being marginalised for holding to those beliefs”.

Military chaplains will still be allowed to preach that homosexuality is wrong, previous reports have said. But the letter wants reassurances that chaplains and troops will be able to be open about their views outside chapels.

The military has not yet commented on the letter.

Earlier this month, the Navy backtracked over plans to allow gay weddings on military bases in states where the practice is legal.

After a memo containing the plans was leaked, another memo was released, saying the plans were “suspended until further notice pending additional legal and policy review and interdepartmental coordination”.

Some politicians had complained that the change would violate the Defense of Marriage Act, which restricts federal recognition of marriage to that of a man and a woman.

The ban on out gay soldiers will not be lifted until military chiefs have certified that repealing the law will not harm military readiness. Following this, 60 days must pass.