House Republican leaders were caught off guard Wednesday afternoon when, during the official unveiling of their “all-of-the-above” energy package, some 200 protesters showed up with pre-printed signs and in costumes to boo the proposal’s call for drilling offshore and in the Arctic National Wildlife Refuge.

The 15-minute GOP event on the West Capitol steps was overrun by members of environmental groups, including the National Wildlife Federation, the Sierra Club and the League of Conservation Voters.

Protesters booed during the news conference and waved signs that read, “Grand Oil Party” and “Climate Action Now;” one person dressed as a polar bear carried the sign, “I love wilderness.”

Michael Steel, spokesman for House Minority Leader John Boehner (R-Ohio), said GOP leaders hadn’t heard of the planned protest until about an hour before the event.

Steel noted that there were cheers amid the boos in the crowd, and those were from “average Americans” who happened to be walking by and listened in.

The fact that so many protesters were on hand shows that Democratic leaders “are extremely concerned” about the merits of the GOP proposal, Steel said.

“Seventy percent of the American people understand that we need real energy solutions” and those include more drilling than Democrats are willing to support, Boehner’s spokesman said.

But Cindy Shogan, executive director of the Alaska Wilderness League, said the GOP energy bill has sparked an “all hands on deck” response from the conservation community.

Speaker Nancy Pelosi (D-Calif.) is “right on target” in opposing offshore drilling and correct to call GOP arguments in favor of drilling in ANWR “a hoax,” Shogan said.

The environmental advocate described a recent trip by House Republicans to the Alaskan Coastal Plain as “a sham.”

“Not only did the group never set foot in the Arctic refuge, but Rep. Boehner didn’t even have the courtesy to respond to a request to meet with the Gwich’in people, who regard the Coastal Plain of the Arctic refuge as the ‘sacred place where life begins,’” Shogan said.