Federline, 44, alleged sons Sean Preston, 16, and Jayden James, 15, "have decided they are not seeing (their mom) right now."
Spears, 40, slammed Federline on her Instagram Story on Saturday calling his interview "hurtful."
"It saddens me to hear that my ex-husband has decided to discuss the relationship between me and my children. As we all know, raising teenage boys is never easy for anyone," she wrote. "It concerns me the reason is based on my Instagram. It was LONG before Instagram."
The pop star added: "I gave them everything."
Spears also claimed her mother Lynne Spears suggested she give majority custody to Federline. She currently has minority custody rights to see Sean and Jayden.
Kevin Federline says sons are uncomfortable with Britney Spears' social media posts
Spears has been posting several risqué topless photos on Instagram, which Federline told the Daily Mail is putting further strain on her relationship with their sons.
Federline claimed to have told their sons, "'Look, maybe that's just another way she tries to express herself.'"
"But that doesn't take away from the fact of what it does to them. It's tough," he said. "I can't imagine how it feels to be a teenager having to go to high school."
In a follow-up post on Instagram, Spears addressed her photos, writing, "Other artists have made much worse when their children were extremely young !!!!!"
She added: "Reminder that the trauma and insults that come with fame and this business not only affect me but my children as well !!!!"
Asghari defended Spears on his Instagram Story. "To clarify my wife has never posted a nude selfie except of her butt (which) is quite modest these days," he wrote. "All other posts were implied nudity (which) can be seen in any ad for lotion or soap."
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Kevin Federline addressed his ex-wife's former 13-year conservatorship
Federline discussed Spears' 13-year conservatorship under her father Jamie Spears, which terminated in November, calling it "hard to watch, harder to live through, harder to watch my boys go through than anything else."
The singer and former backup dancer said in his interview Saturday that he believes Jamie "saved" Spears' life.
"They've had a lot of questions about it," Federline shared. "I don't know that I can answer all of them for them, but I just tried to explain to them that your mom needed help, you know, and the people were in play to try to make that happen, to make it better."
Federline was previously at odds with Jamie. In 2019, he took out a restraining order against Jamie following an "inappropriate physical altercation" with Sean during a visit at his home in Westlake Village, according to Federline's longtime lawyer, Mark Vincent Kaplan, who accompanied Federline when he filed the complaint.
District Attorney Gregory Totten decided not to pursue criminal charges against Jamie after investigating "allegations of child abuse."
"After reviewing the evidence, there is insufficient proof that a criminal offense was committed by Mr. Spears," Totten concluded.
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Despite the strained relationship, Federline said Jamie is still "welcome" into his grandson's lives "if that's what the boys wanted."
He added: "I don't have any hard feelings toward Jamie Spears. People make mistakes. I feel bad for him. I feel like he's been put through the wringer."
In their public spat, Asghari said it's "irresponsible" for Federline to have made those statements and "vilify" Spears.
"His character is revealed by approval of the cruel 13 year CShip and his loyalty to Jaimie indicates his approval at time of its conception as well," the model wrote.
Asghari also defended his wife by saying her mental health concerns could have "easily (been) dealt with (in) therapy. … Anyone approving of it is wrong of benefiting from it somehow."
"I wish him the best and hope he has a more positive outlook in the future for benefit of all involved," he added.
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Contributing: Maria Puente
This article originally appeared on USA TODAY: Britney Spears slams Kevin Federline after claims on kids' visitation