U.S. and Canadian customs and border agents said drug smugglers used helicopters and small planes to move tons of marijuana and other drugs across the border.

Officials said aircraft dropped drugs at sites on public lands throughout the region, including locations in the Mount Baker-Snoqualmie and Okanogan National Forests and the North Cascades National Park.

The operation has resulted in 40 arrests in a year and a half.

"These organized criminal groups are motivated by one thing: greed," said John McKay, U.S. attorney for the western district of Washington. "With Operation Frozen Timber, we not only cut into their profits with countless seizures of drugs and money, we demonstrated that there is a high price to pay."

McKay said the ring leader, Robert Kesling, is serving 17 years in federal prison.