WASHINGTON — Fearing a Russian invasion and occupation of Alaska, the U.S. government in the early Cold War years recruited and trained fishermen, bush pilots, trappers and other private citizens across Alaska for a covert network to feed wartime intelligence to the military, newly declassified Air Force and FBI documents show.

Invasion of Alaska? Yes. It seemed like a real possibility in 1950.

“The military believes that it would be an airborne invasion involving bombing and the dropping of paratroopers,” one FBI memo said. The most likely targets were thought to be Nome, Fairbanks, Anchorage and Seward.

So FBI director J. Edgar Hoover teamed up on a highly classified project, code-named “Washtub,” with the newly created Air Force Office of Special Investigations, headed by Hoover protege and former FBI official Joseph F. Carroll.

The secret plan was to have citizen-agents in key locations in Alaska ready to hide from the invaders of what was then only a U.S. territory. The citizen-agents would find their way to survival caches of food, cold-weather gear, message-coding material and radios. In hiding they would transmit word of enemy movements.