Kayak protesters try to stop Shell oil rig from leaving Seattle, heading to drill off Alaska

Greenpeace says 13 protesters in kayaks formed a blockade to try to stop Royal Dutch Shell's drill rig from leaving Seattle on its way to explore for oil in the Arctic Ocean.

Group spokeswoman Cassady Sharp said the Coast Guard has arrested several of the "kayaktivists" who paddled out to stop the Polar Pioneer around 4 a.m. Monday. She says about 40 to 50 supporters in kayaks and canoes lined up behind the blockade.

The petroleum giant's plans to drill in the waters off Alaska drew a similar kayak protest in May. Activists also have chained themselves twice to a support ship in Bellingham, north of Seattle.

Shell spokesman Curtis Smith says the company remains "committed to operating in a safe, environmentally responsible manner."

The Coast Guard didn't immediately respond to a phone message seeking comment.