It was all out war at Katherine Jackson's house in Calabasas Monday ... complete with slapping and punching ... TMZ has learned.
We now have details about the incident. Sources who were there say two SUVs with Randy, Jermaine and Janet inside, followed a car driving Michael Jackson's 3 kids inside the gates. We're told Randy, Jermaine and Janet did not have authority to enter.
Once on the grounds, we're told MJ's 3 siblings tried to strong-arm Paris, Prince and Blanket. Their mission was to get them in an SUV and take them to Arizona, where Katherine has been staying.
Our sources say at one point Janet tried to grab a resistant Paris' cell phone, a scuffle ensued and Janet slapped the teenager, screaming, "You're a spoiled little bitch!" We're told Paris fired back with her own slap and told Janet, "This is our house. Not the Jackson family house. Get the f**k out!"
At the same time, we're told Trent Jackson, who was at the house, tried to stop an aggressive Randy and Jermaine. We're told Trent put Randy in a headlock and punched Jermaine in the mouth.