Kate and Jon Gosselin

The Gosselin's twin girls, Cara and Mady, turned 9 years old on Thursday, but Jon says Kate is trying to keep him from joining in on their birthday festivities.

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"She's trying to prevent me from seeing my kids on Mady and Cara's birthday," Jon told Entertainment Tonight. "That's like giving her full custody by obeying her."

The father of eight said he Kate requested they alter their custody agreement so that he would only be present at the family's Pennsylvania home from 4 p.m. to 6 p.m. on Thursday for the birthday party.

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"Due to recent events, it will be too stressful to the kids to have both of us here as planned. I would like to split the evening so they can see us both," Jon claims an email from Kate read.

Jon said he's "not going to allow it" and will just stay over at the family home. "I own the house, so I can do what I want," Jon said.

"It's an all-out battle," Jon added. "She can't tell me what to do."