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More than A DOZEN cop cars and TWO police helicopters raced to Diddy's L.A. home moments ago ... but law enforcement sources tell TMZ the incident is yet another "swatting" prank.

Law enforcement sources tell us ... a swatter made a call that someone was shot inside the home.

Sources at the scene tell us ... cops are already dispersing ... and officials now know it was another celebrity swatting prank.

We were initially told the target was Steve Carell ... there were multiple cop cars in his driveway.  We're told cops secured his house because it's right next to Diddy's.
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In fact, Diddy isn't the first star on his block to have been swatted -- Miley Cyrus' parents' home was targeted in a similar prank last year.

FYI -- cops take the swatting thing VERY seriously ... and have said they will prosecute the perpetrator to the fullest extent of the law.