The aircraft, a Cessna 208, vanished during a flight from neighbouring Idaho to Shelton, in southwest Washington on Sunday, said Jake Weber of the Yakima County search and rescue team.

The passengers on board the plane were all part of a skydiving team returning from a competition in Boise, Idaho, Weber said.

The plane was believed to have gone down on the eastern side of the Cascade Mountain range, southeast of Seattle, officials said.

"Rescue crews are scouring the forest area, no emergency beacon has been located, but, they have a radar ping of the last known location," Weber said.

Nisha Marvel, of the Washington department of transport, told CNN officials were alerted after the plane failed to reach its destination on Sunday.