FORT RILEY, Kan. — When Specialist Jeremy Hall held a meeting last July for atheists and freethinkers at Camp Speicher in Iraq, he was excited, he said, to see an officer attending.

But minutes into the talk, the officer, Maj. Freddy J. Welborn, began to berate Specialist Hall and another soldier about atheism, Specialist Hall wrote in a sworn statement. “People like you are not holding up the Constitution and are going against what the founding fathers, who were Christians, wanted for America!” Major Welborn said, according to the statement.

Major Welborn told the soldiers he might bar them from re-enlistment and bring charges against them, according to the statement.

Last month, Specialist Hall and the Military Religious Freedom Foundation, an advocacy group, filed suit in federal court in Kansas, alleging that Specialist Hall’s right to be free from state endorsement of religion under the First Amendment had been violated and that he had faced retaliation for his views. In November, he was sent home early from Iraq because of threats from fellow soldiers.

Eileen Lainez, a spokeswoman for the Defense Department, declined to comment on the case, saying, “The department does not discuss pending litigation.”