BREAKING: A horrific mass shooting has unfolded at a birthday gathering in Stockton, California — and the situation is still developing.

At least 19 people have been shot, including children as young as 9 and 12. Officials have confirmed four fatalities, and warn that number may rise.

Multiple kids were pulled from the scene needing CPR.
Families were celebrating moments before chaos erupted.

The shooter is still on the run, and police are flooding the area.

Avoid the neighborhood — this is active and ongoing.