Video captured at Yellowstone National Park shows a group of tourists fleeing a mother black bear and her three cubs.

According to reports, the bears unexpectedly appeared on a bridge, which was lined with tourists.

The footage shows the tourists running - or walking - away from the bears as Yellowstone Park Ranger John Kerr is heard in the background yelling, "Keep going! Go! Go!"

The mother bear even ends up charging at one family as they scramble to their vehicle.

No people or bears were hurt in the incident.

Yellowstone regulations require visitors to stay at least 100 yards away from bears at all times.

Watch the video above.

You might also be interested in ...

MUST-SEE VIDEO: Adorable Family of Bears Takes a Dip

Oscar the Lonely Himalayan Black Bear Desperately Seeking New Home in U.S.

Hunter Survives Brutal Bear Attack, Thanks to 5-Inch Knife

Watch: Russian Man Feeds Hungry Bear Through Window