Franklin Graham has sprung to the defence of former Atlanta fire chief Kelvin Cochran, sacked because he wrote a book stating traditional Christian beliefs about marriage and homosexuality.

In an opinion piece for Charisma News, the leading evangelical accused the city of "politically correct bullying", saying: "The book on biblical morality simply restates God's position put forth in His Word, the Bible."

He paid warm tribute to Cochran, saying: "I personally know Chief Cochran. He served as chairman of my Crusade in Shreveport in 2005. He is a fearless man of great faith."

The book was brought to the attention of Atlanta city council member Alex Wan, who is gay. Graham said: "Because Cochran expressed his biblical belief on sexual purity in general—not only on homosexuality—an openly gay city council member went on a rampage to discredit this upstanding servant of the community. Cochran didn't discriminate against anyone, he didn't persecute anyone for homosexuality or create a hostile work environment. Instead he was persecuted and denied his career because of his privately held religious beliefs. This is true discrimination."

He concluded: "The LGBT community wants us to be afraid of expressing our Christian beliefs. They want us to cower in the face of their threats to the livelihoods of believers. But we shouldn't back down!"

Cochran self-published the 162-page book last year entitled Who Told You That You Are Naked?, aimed at helping men overcome feelings of guilt over past sins. It defines 'uncleanness' as the "opposite of purity; including sodomy, homosexuality, lesbianism, pederasty, bestiality, and all other forms of sexual perversion". It discusses homosexuality in half a page.

Cochran is a deacon, Sunday School teacher and Bible study leader at Atlanta's Elizabeth Baptist Church.

Atlanta's Mayor Kasim Reed said at a press conference about the sacking: "Despite my respect for Chief Cochran's service, I believe his actions and decision-making undermine his ability to manage our fire department.

"Every single employee under the fire chief's command deserves the certainty that he or she is a valued member of the team and that fairness and respect guide employment decisions. His actions around the book and his statements during this investigation have eroded my confidence in his ability to convey that message."