The Catholic Church in Scotland has accused the SNP of discriminating against party members who oppose abortion and gender fluidity.
Anthony Horan, director of the Catholic Parliamentary Office in Scotland, told The Times that pro-life members like Dr Lisa Cameron, SNP MP for East Kilbride, Strathaven & Lesmahagow, had been the victim of "open and vicious hostility".
Dr Cameron broke ranks with the party to vote against relaxing abortion regulations in Northern Ireland, a move she said led to "attacks" against her.
Mr Horan suggested that the party was trying to stop members with traditionalist views from being selected for elections to Holyrood next year.
He expressed concerns that officials at individual SNP branches across the country may be discriminating against party colleagues over their views on religion, the unborn and biological sex.
"Alarmingly, recent reports suggest that religious affiliation, pro-life beliefs and the belief that gender is not fluid and changeable may lead to some individuals being excluded from the SNP candidate selection process ahead of next year's Scottish parliament elections," he said.
The reports would "undermine entirely" Nicola Sturgeon's claims to be "proud of" diversity in the party if found to be true, he said.
Mr Horan added: "It is of paramount importance that all parties respect the right to freedom of conscience in their candidate selection process and that a diversity of views is not simply tolerated, but welcomed, including the belief in the dignity of human life in the womb and the right to disagree with transgender ideology."
An SNP spokesman told the paper: "We are proud of the diversity in our party and no one is failed at assessment because of their religious views."