POWELL, Mont. (AP) - A huge truckload of oil refinery equipment has left Idaho and the hundreds of protesters who tried to slow and even stop its advance through tribal lands and a federally protected river corridor.

The 644,000-pound load is now parked in Montana, where it will resume its journey en route to the tar sands project in Alberta, Canada.

The megaload - 244-feet long and 21-feet wide - left the Port of Wilma, near Clarkston, Wash., Monday night and was met by hundreds of protesters each of the next four nights as it traveled U.S. Highway 12 across northcentral Idaho.

Opponents of the shipments and Oregon-based hauler Omega Morgan sought to slow or halt the truck by standing in the roadway and filing legal action in federal court. More than two dozen protesters, including leaders of the Nez Perce Tribe, were arrested and charged with misdemeanors by tribal police.

On Thursday, attorneys for the Nez Perce Tribe and Idaho Rivers United filed a complaint in federal court asking a judge to issue an order halting the shipment. Attorneys for Omega Morgan have not yet filed a response to the lawsuit and U.S. District Judge B. Lynn Winmill has yet to schedule any hearings in the matter.

"We don't expect to see anything until early next week," Kevin Lewis, conservation director for IRU, told the Lewiston Tribune in a story published Saturday.

Now in Montana, the load is expected to travel through Missoula, cross Roger's Pass on to Montana Highway 200 then head north through the cities of Choteau and Cut Bank. It's slated to enter Canada at the Port of Sweetgrass. It's barred from traveling on any interstate roadway because the load's height of 23 feet violates interstate requirements.

Duane Williams, director of motor carrier services for the Montana Department of Transportation, said he doesn't anticipate any glitches for the load in his state.

The load is the first of several that Omega Morgan hopes to haul along the same route, despite the anger and litigation the first load launched in Idaho.

In the lawsuit, the tribe and IRU accuse the U.S. Forest Service of shirking its duty to stop the shipment from entering a section of the highway that passes through a federally designated Wild and Scenic River corridor. The two-lane roadway traces the Lochsa and Clearwater rivers, an area protected under the 1968 Wild and Scenic Rivers Act.

Earlier this year, Judge Winmill, presiding over a separate lawsuit on a previous megaload shipment, ruled the Forest Service has the authority to review state permitting plans for over-legal loads passing through the corridor. Forest officials say they have not yet developed the criteria for reviewing megaload permits and last week urged Omega Morgan officials to hold off moving the first shipment across Idaho.