WASHINGTON (AP) _ Government property managers are ordering the Forest Service to confiscate 35 airplanes it traded to private firefighting contractors in a case one congressman says involved CIA missions in the Persian Gulf.

Two of the former military planes were the target of a congressional hearing in 1993 after they turned up hauling cargo for pay in Kuwait in 1991 following the war in Iraq.

In a letter that The Associated Press obtained Friday, the General Services Administration said the aircraft should never have been turned over to Forest Service contractors.

Then-Forest Service Chief Dale Robertson told Congress in 1993 that ``mistakes were made'' but that no laws broken when 23 C-130 Air Force cargo planes and 12 P-3A Navy planes were transferred to the Forest Service, then into the hands of preferred contractors.

But the GSA told the Forest Service in the Sept. 21, 1995, letter that a federal probe in Arizona has produced evidence that the exchange program was illegal.

``Based upon information received from the United States attorney in Tucson, we have determined that the Forest Service illegally removed these aircraft from its inventory,'' said the letter by Peggy Lowndes, chief of the GSA's property management branch in San Francisco.

``Since the exchanges of these aircraft were not performed legally, these aircraft are still the property of the Forest Service. You should take immediate action to bring them under your control and place them back on your property account,'' Lowndes wrote to Ron Hooper, Forest Service deputy for procurement and property.

Lowndes declined to comment Friday, citing the sensitive nature of the ongoing criminal investigation.

The Justice Department began investigating in 1993, Assistant Agriculture Secretary James Lyons said, but it has brought no charges.

The planes were to be used only for fighting forest fires, but Lyons acknowledged during a congressional hearing in August 1993 that several of the planes wrongly flew supply missions in Kuwait during the Persian Gulf War.

``We don't have any comment until we complete our talks with the Department of Justice and GSA,'' USDA spokesman Tom Amontree said Friday.

Rep. Charlie Rose, D-N.C., former chairman of the House Agriculture subcommittee on forestry, said during the hearing he was convinced the CIA was running covert operations with the planes. ``This situation stinks to high heaven,'' he said.

The planes, considered military surplus and valued at $65 million to $80 million, were given free of charge to Forest Service contractors that had given their own planes to government museums as historic aircraft.

Recipients included: T&G Aviation Inc. of Chandler, Ariz.; Hawkins & Powers Aviation Inc., of Greybull, Wyo.; Hemet Valley Flying Service of Hemet, Calif.; T.B.M. Inc. of Tulare, Calif.; and Aero Union Corp. of Chico, Calif.

Agriculture Department investigators said in a November 1992 audit that Roy D. Reagan of Medford, Ore., who arranged most of the plane swaps, made more than $1 million in reselling four of the aircraft.

Spokesmen for all five companies said they had not seen the GSA letter and had no immediate comment. Reagan could not be reached for comment Friday.