SAN DIEGO (AP) - Authorities say at least four people were killed after two small planes collided in the air near an airport in southern San Diego County.

Federal Aviation Administration spokesman Ian Gregor says the collision occurred around 11 a.m. Sunday about 2 miles northeast of Brown Field Municipal Airport.

The planes - a twin-engine Sabreliner and a single-engine Cessna 172 - caught fire when they hit the ground and broke apart.

Nick Schuler with the California Department of Fire and Forestry said first responders initially reported three fatalities.

But as they inspected the wreckage which was scattered across a quarter-mile area, they determined that at least four people were killed.

The FAA and National Transportation Safety Board will investigate the collision.