WASHINGTON — A conservation group says it will appeal a Wyoming federal judge's decision to allow more snowmobiles into Yellowstone and Grand Teton national parks.

In papers filed in Washington, the Greater Yellowstone Coalition said it will ask Judge Clarence Brimmer of Wyoming to suspend his order until the appeal can be dealt with by the 10th U.S. Circuit Court of Appeals in Denver.

On Tuesday, Brimmer ordered the National Park Service to stop implementing a plan that cut the number of snowmobiles allowed in the parks this winter and that would have called for an all-out ban on the machines next winter.

That plan, written by the Clinton administration, was set aside by the Bush administration to settle a lawsuit before Brimmer.

The Bush administration wrote a new plan, which was to begin in December, that would have allowed snowmobiling to continue — under daily limits on the number of machines allowed into the parks and with new requirements for the machines to run on cleaner and quieter engines.

But in a separate lawsuit filed by the Greater Yellowstone Coalition, U.S. District Judge Emmet Sullivan in Washington struck down the Bush plan in December. Sullivan said the Park Service was not justified to rewrite the rules and ordered the Clinton plan, which would replace snowmobiles with mass-transit snow coaches for tourists, put in place.

The Clinton plan would have eventually banned snowmobiles. The Bush administration said its restrictions and new emission requirements would protect resources while allowing snowmobilers to continue to visit the parks in the winter.

Brimmer issued an injunction stopping the Park Service from implementing the Clinton plan earlier this week. He instead ordered it to write temporary rules for this winter.

In response to Brimmer's ruling, the Park Service on Wednesday issued new rules that allow more snowmobiles into the parks than Sullivan's December ruling had allowed. Some must be the cleaner and quieter machines, and all must be part of commercially guided trips.