Britney Spears’ father was accused of physically abusing her oldest son during an argument last month, prompting ex-husband Kevin Federline to order a restraining order against the boy’s grandfather.

A police report obtained by Us Weekly detailed an Aug. 24 incident involving Jamie Spears, 61, and the singer’s oldest son Sean Preston, 13.

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Sean and his younger brother Jayden James, 12, were visiting their grandfather at his condo in California when he allegedly got into an argument with Spears. He reportedly “felt unsafe” and locked himself in a room but Spears managed to break in and allegedly “shook” the boy, a law enforcement source told the magazine.

Britney, 37, took her two boys from the home and returned them to Federline, the outlet reported, who was recently granted 70 percent custody.

Federline filed a police report the following day and was granted a domestic violence restraining order against Jamie, barring him from seeing the boys, the New York Daily News reported.

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The Ventura County Sheriff’s Office, where the police report was filed, did not immediately return Fox News’ request for comment.

Britney and Federline officially divorced in March 2007, at which time he maintained sole custody of the children following the singer's widely publicized breakdown. The couple recently reached a new custody agreement where she will now have 30 percent going forward and will not require supervision.

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An attorney for Federline told the Daily News following reports of the alleged abuse that “Kevin wants to assure that Britney has the most reasonable custody with the kids that is consistent with their best interests” but added that “the kids love their mother, and Kevin doesn’t want to do anything that would be inconsistent with that.”

A rep for Britney did not return Fox News’ request for comment. A rep for Jamie was not made immediately available for comment.

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Her father Jamie has been her conservator since her 2008 and in May a judge in Britney's conservatorship case ordered a 730 evaluation, a process usually used to determine the mental health and competence of a parent in a divorce case.

Fox News’ Jessica Sager contributed to this report.