The Coast Guard says protesters opposed to offshore drilling in the Arctic will have to stay in safety zones when a drill rig arrives in Seattle.

Chief Petty Officer Sara Mooers says a Seattle-bound drill rig and a heavy-lift vessel are expected to arrive in Port Angeles later this week, though an exact day wasn't known. She says when the rig and vessel enter Elliott Bay off Seattle protesters will have to stay 500 yards away from a moving vessel and 100 yards from one that is anchored.

Conservationists oppose Arctic offshore drilling and say oil companies have not demonstrated they can clean up a major spill.

Protesters have said they plan use kayaks to meet the 400-foot Polar Pioneer and the heavy-lift vessel called the Blue Marlin that is carrying it when the vessel comes to Seattle for staging.

"We fully support people exercising their First Amendment rights, but there's a lot of activity in Elliott Bay," Mooers said.

Royal Dutch Shell hopes to use the rig for exploratory drilling during the summer open-water season in the Chukchi Sea off Alaska's northwest coast if it can obtain the necessary permits.

A U.S. District Court judge has granted Shell a restraining order against the protesters. The order prohibits Greenpeace activists from entering any safety zone around the rig and the Blue Marlin.

On Saturday, six Greenpeace activists opposed to offshore drilling in the Arctic abandoned the Seattle-bound drill rig they boarded in the Pacific Ocean on April 6. The six had climbed on Polar Pioneer about 750 miles northwest of Hawaii.

Shell has also asked the court for an injunction against further Greenpeace actions on Shell ships bound for or already in the Arctic. The court issued a similar order in 2012, the last time Shell conducted exploratory drilling in the Arctic.

Greenpeace spokeswoman Cassady Sharp said in a statement that Shell was trying to silence public opposition to its plans.

"The climate movement throughout the Pacific Northwest has shown its commitment to speaking out for the Arctic," she said. "And we expect that to continue."