Las Vegas — Federal authorities are asking for the public's help in tracking down two men seen damaging rock formations at a national recreation site in Nevada.

Officials at Lake Mead National Recreation Area said on social media that the damage happened during a recent weekend near the Redstone Dune Trail on the north side of the lake. The petrified red dunes found there make it one of the most popular hiking spots in the park.

A video that CBS Las Vegas affiliate KLAS-TV says has gone viral that Lake Mead said was recorded on the evening of April 7 shows two men shoving chunks of sandstone off the edge of an outcropping as a girl screams. Park officials called the behavior appalling, saying the damage can't be fixed.

"It's one of my favorite places in the park and they're up there just destroying it. I don't understand that," John Haynes, public information officer at Lake Mead National Recreation Area, told television station KVVU.

Destruction like this at federally protected sites can result in felony charges that come along with potential fines and jail time, Haynes said.

Spanning 2,344 square miles of mountains and desert canyons, the Lake Mead National Recreation Area just outside Las Vegas draws around 6 million visitors every year. Officials said staffing levels mean park officials often rely on the public to also keep watch over resources within park boundaries.

Authorities said visitors can use their cellphones to capture any video or photos of suspicious activity if it's safe to and to collect any information, such as a license plate, that might help identify offenders. The National Park Service operates a tip line that receives thousands of submissions each year. That number is 888-653-0009, and there's an online version.

"It's really important to let us know," Haynes said.

There also have been others cases of vandalism on federal land across the West over the past decade, with visitors defacing petroglyphs, toppling rock features and pounding climbing bolts into centuries-old rock art.