PORTLAND, Ore. (AP) _ An underground group of environmental activists claimed responsibility for a December fire at the U.S. Forest Industries headquarters in Medford.

In a fax sent to The Associated Press late Saturday, The Earth Liberation Front said the Dec. 26 fire was ``in retribution for all the wild forests and animals lost to feed the wallets of greedy'' corporations.

``They have a clear political and social purpose, that's to end the exploitative and abusive industry practices at hand,'' said Craig Rosbraugh of the Portland-based Liberation Collective, who serves as a spokesman for the underground group.

Police declined to comment until they could investigate.

The fax read, in part: ``On the foggy night after Christmas when everyone was digesting their turkey and pie, Santa's ELFs dropped two five-gallon buckets of diesel/unleaded mix and a one gallon jug with cigarette delays; which proved to be more than enough to get this party started.''

The office that burned was headquarters for four mills _ a White City veneer mill, a Grants Pass plywood mill, a stud mill in Colorado and a sawmill in Florida. Damage was estimated at $500,000.

A telephone message left Sunday at the home of Jerry Bramwell, president of U.S. Forest Industries, was not immediately returned.

Last fall, ELF claimed responsibility for an Oct. 12 fire at Vail, Colo., that destroyed four ski lifts, a restaurant, a picnic facility and a utility building.

ELF members also claimed responsibility for arson fires two years ago at two ranger stations in the Willamette National Forest in Oregon.