Paris, Prince and Blanket are prohibited from seeing their aunts and uncles at Katherine Jackson's Calabasas home ... all because of Katherine's nephew, Trent, according to a Jackson family source.

Janet, Jermaine and Rebbie's son Austin all showed up at Katherine's estate to speak with Michael's three children to tell them "they can go see their grandmother anytime."

However, Trent Jackson, using "military-style security tactics," would not allow them to visit, according to a source. Trent is also the same family member who's part of an ongoing investigation involving elder abuse.

A Jackson family source tells X17online exclusively:

    "Trent has instructed security to not allow family into the home. The kids were told they had every right to come visit their grandma in Arizona, but they flat out said 'we don't want to.' Now Trent is telling the cooks and the staff to not show up to work so that it looks like the children aren't being cared for. He knows he's been caught and now he's trying to use the children to cover it up."

The family source adds, "Paris has confided in her cousins that Trent and a security member have been "putting her up to Tweeting out messages against the family."

As for why the kids declined an offer to visit their grandmother, our source adds,

    "Paris is trying to get out of going to summer school and without her grandmother there, she's succeeding. She's extremely manipulative and just wants to stay home and have fun. And at only 15, Prince is trying to get his girlfriend to come stay at the house. With Trent overseeing the children, it's complete chaos and they have no boundaries."

X17online exclusively obtained the photo of Katherine Jackson visiting her daughter Rebbie in Arizona and enjoying the card game, Uno. Arizona Sheriff's authorities have confirmed that the Jackson matriarch is "having a good time with family."