CHEYENNE, Wyo. (AP) -- A federal appeals court upheld the dismissal of Wyoming's lawsuit against the federal government over how wolves should be managed in the state after their removal from Endangered Species Act protection.

Wyoming filed suit after the U.S. Fish and Wildlife Service rejected its plan for managing wolves in 2004. The agency is requiring Montana, Idaho and Wyoming to submit acceptable plans for managing the animals before it will remove them from the endangered species list.

The Montana and Idaho plans were accepted. Wyoming's was rejected in part because it would classify wolves as a potential nuisance that could be shot on site outside the Yellowstone area.

In a four-page ruling Monday, the 10th U.S. Circuit Court of Appeals in Denver upheld a ruling by U.S. District Judge Alan Johnson in March 2005.

Johnson had denied the state's claim that the federal government violated the Endangered Species Act in rejecting the plan. He ruled that the Endangered Species Act didn't come into play because the rejection didn't determine wolves' status under the act.

An intervener in the case on Wyoming's side did not rule out appealing to the U.S. Supreme Court. "It's certainly not the end of the battle," said Bryan Skoric, the county attorney in Park County, which intervened in the case about a year ago.

He said the Yellowstone region, more than a decade after wolves were first reintroduced there, now has more than 1,000 wolves. He said the federal government had set 315 wolves as the goal population.

"We have to ask ourselves how long is this going to go on?" he said.

He accused the Fish and Wildlife Service of failing to act. But Earthjustice attorney Abigail Dillen said wolves might have been delisted by now if Wyoming had not taken the dispute to court.

"From a legal point of view, I don't think the decision is surprising at all," she said. "From a practical point of view, it is time for Wyoming to get serious about affording wolves some protection outside of Yellowstone National Park. Allowing wolves to be shot on site outside Yellowstone is not the answer."

Dillen represents the Sierra Club and Natural Resources Defense Council, which intervened on the side of the federal government.

Oral arguments before the appeals court took place in Salt Lake City last month. Attorney General Pat Crank said he got an idea from those proceedings that the appeals court wouldn't rule in Wyoming's favor.

"They were asking a lot of questions why this wasn't some regular advice the Fish and Wildlife Service was handing out rather than a formal agency action as defined by federal law," he said of the rejection of Wyoming's plan.

Wyoming has petitioned to have wolves delisted and the federal government is expected to decide on that request by July 15. "If they don't proceed forward with delisting, we can seek review of that decision in federal District Court," Crank said.

Johnson had said that the Endangered Species Act's requirements for scientific review only would come into play with delisting, or when wolves come up for status review under the act in 2008 -- five years after they were downgraded in parts of the West from "endangered" to "threatened."

Associated Press reporter Jennifer Byrd contributed to this report.