In a statement, Clooney said Wednesday that the claims about his future mother-in-law, Baria Alamuddin, were untrue and irresponsible.
Clooney and London lawyer Amal Alamuddin announced their engagement in April. Beirut-born Alamuddin comes from a Druse family – adherents of a monotheistic religion based mainly in Lebanon, Syria and Israel.
The Daily Mail cited unnamed "friends" as saying Amal Alamuddin risked being "cast out of the community" because she was not marrying a Druse man. The newspaper said "several women have been murdered" for not abiding by strict Druse rules.
Clooney said in a statement that "none of the story is true. Amal's mother is not Druse. She has not been to Beirut since Amal and I have been dating, and she is in no way against the marriage."
Indeed, Clooney's future mother-in-law is elated about the upcoming nuptials between her daughter and the actor, a source close to the family tells PEOPLE.
"Baria is very happy and in seventh heaven," the source says.
Clooney added that "to exploit religious differences where none exist is at the very least negligent and more appropriately dangerous."
"We have family members all over the world, and the idea that someone would inflame any part of that world for the sole reason of selling papers should be criminal," he said.
Shortly after the release of Clooney's statement, The Daily Mail issued an apology, saying Wednesday that the story had been "supplied in good faith by a reputable and trusted freelance journalist."
"We accept Mr. Clooney's assurance that the story is inaccurate and we apologize to him, Miss Amal Alamuddin and her mother, Baria, for any distress caused," the paper said in a statement.
The Mail said it has removed the article from the website "and will be contacting Mr. Clooney's representatives to discuss giving him the opportunity to set the record straight."
Clooney, 53, was married to actress Talia Balsam from 1989 to 1993. This will be the first marriage for 36-year-old Alamuddin.
The Druse are a close-knit community and rarely marry outside their sect. But some Druse have welcomed Clooney.
Walid Jumblatt, political leader of the sect in Lebanon, told the Associated Press recently that he hoped the couple would soon visit the Druse heartland.
Clooney will bring us "great publicity," Jumblatt said. "He can make a movie about the Druse sect."
With reporting by PETER MIKELBANK