Protesters hang a sign on Mount Rushmore

MOUNT RUSHMORE, S.D., July 8 (UPI) -- A group of protesters scaled South Dakota's Mount Rushmore Wednesday to hang a banner protesting inaction on global warming and were promptly arrested.

Members of Greenpeace called on world leaders attending the Group of Eight summit in L'Aquila, Italy, to give a higher priority to stopping global warming when they stretched a 2,275-square-foot sign across the monument. The sign read, "America honors leaders not politicians: stop global warming."

About a dozen protesters were arrested, Marty J. Jackley, U.S. attorney for the District of South Dakota, told CNN. Some reached the top of the monument after breaching a controlled area, Patty Rooney, a spokeswoman for Mount Rushmore, said. Park staff were alerted by a security system.

Rooney said the monument will be assessed for any structural damage, and the banner will be removed as soon as it can be done safely. She said a security system alerted park staff to the protest at midday.

Greenpeace officials said they don't believe they damaged the monument, while admitting the move was dangerous and illegal, CNN reported.