Sandra Bullock is in the middle of a vicious baby battle!

The “Speed” star is rallying behind hubby Jesse James in his fight to win custody of his 3-year-old daughter Sunny from his ex-wife, porn star Janine Lindemulder, say sources.

But Janine is not giving up easily – and insiders say she blames the 42-year-old “Miss Congeniality” beauty for pushing Jesse to snatch Sunny away from her.

Jesse, host of TV’s “Monster Garage,” filed an emergency child custody order against Janine on March 15. He asked the court to award him temporary custody of Sunny pending a child welfare investigation.

In court documents, 37-year-old Jesse claimed that Sunny was scratched and bruised when she visited him and Sandra recently – and the child blamed “mommy’s chair” for her injuries.

“Sunny had small scratches and what appeared to be broken blood vessels and a bruise on her left cheek and a few bruises around her left and right eye,” Jesse said in papers filed in California’s Orange County Superior Court.

“When my wife gently asked her if it hurt she said: ‘Yes, but the bleeding stopped.’ She just said ‘mommy’s chair’ when we asked how it happened.”

The papers also state Janine “was to pick her up on Saturday afternoon but when she arrived (an hour late), Sunny screamed and cried she didn’t want to go.

“My wife and I let Sunny stay with us in bed Saturday night. We didn’t think she should be alone. During the night she was very restless and seemed to be angry and crying off and on, but clearly cried out: ‘don’t touch me’ and ‘don’t do that.'”

Jesse – who now has limited custody of Sunny – says he’s willing to drop his court action against Janine if she gives him 50 percent custody of their daughter.

But Janine claims in court documents that before January, Jesse had seen his daughter only once – on the day she was born – and that was only for about 30 minutes!

“Janine wants Jesse to be in Sunny’s life, but she won’t give him 50 percent custody,” said a source.

Meanwhile, Janine blames Sandra – who wed tattooed biker Jesse in July 2005 – for pushing the custody issue.

“Janine doesn’t have any problems with Sandra, but she does think it was Sandra who convinced Jesse to take a more active role in his daughter’s life,” said the source.

As for Jesse’s suit against her, the source said: “Janine is a loving, caring mother. She welcomes any sort of investigation into her household. She has nothing to hide.

“Just because she’s a porn star people automatically assume she’s not a good mother – and that’s simply not true!”