LIVERMORE, Calif. —  A flight instructor and student have been killed in a helicopter crash near a Northern California freeway that knocked power lines into traffic lanes and started a grass fire.

Federal Aviation Administration spokesman Ian Gregor says the Schweizer helicopter crashed and caught fire after striking power lines just east of Interstate 680 in Livermore at about 12:30 a.m Friday.

He says the two victims had departed from Reid-Hillview Airport in San Jose and had planned to return to that facility.

It wasn't known whether the instructor or student had been piloting the Model 269 Series helicopter. Their names weren't immediately released.

The weather was cloudy at the time of the crash.

Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.