George Washington, Abraham Lincoln, Thomas Jefferson, Theodore Roosevelt and . . . Barack Obama?

Patriotic tourists visiting the Mount Rushmore National Memorial in South Dakota on Wednesday found a fifth face displayed -- and not as a compliment -- next to the giant stone carvings of four legendary presidents.

A group of environmental activists connected with Greenpeace unfurled an enormous banner showing President Obama's face and calling for an end to global warming.

The 65-foot by 35-foot banner — which read "America Honors Leaders, Not Politicians: Stop Global Warming" — was hung to the immediate right of Lincoln at about 10 a.m. local time, said Patty Rooney, a spokeswoman for the National Park Service's Midwest Regional Office.

She said an undetermined number of people were taken into custody following the incident.

Daniel Kessler, a spokesman for Greenpeace, said 11 people were detained, but it was not clear how many of them were Greenpeace employees.

No injuries were reported.

Park workers are trying to remove the banner, Rooney said, but strong winds have complicated the process.

"It is not down yet," she said shortly before noon.

She said park workers will assess damage to the 5,725-foot mountain once the banner is down.

Eleven activists climbed to top of the mountain as part of several demonstrations by the Greenpeace, which is calling for more aggressive action to combat climate change as world leaders meet at the Group of Eight summit in L'Aquila, Italy.

Three of those 11 activists rappelled down and hung the banner as they descended, Kessler said. A video of the incident was posted on the group's Web site.

"This monument celebrates leaders who rose to the great challenges of our past," Greepeace USA Deputy Campaign Director Carroll Muffett said in a press release. "Global warming is the greatest crisis humankind has ever faced and it is the defining test of leadership for this generation. It's an open question whether President Obama will pass this test."

Other demonstrations held by Greenpeace on Wednesday included the hanging of banners on smokestacks at a coal plant in Italy.

"Doing what it takes to solve global warming demands real political courage," Muffett continued. "If President Obama intends to earn a place among this country's true leaders, he needs to show that courage, and base his actions on the scientific reality rather than political convenience."

The 11 activists were later arrested and charged with trespassing, the Associated Press reported Wednesday night.