An officer shot and killed a dog after it charged at him at the Rainbow Family Gathering in eastern Oregon, the U.S. Forest Service said.

The gathering in the Malheur National Forest has drawn more than 2,600 people. As many as 20,000 are expected for the July 1-7 festival.

A Forest Service law enforcement officer was conducting a routine car count in the festival's parking lot on Tuesday morning when he noticed two dogs sitting about 15 feet away from him, Forest Service officials said.

One of the dogs, a pit bull mix, started to walk toward the officer, officials said. When the officer stepped back, the dog began to run at him.

The officer then fired a single shot at the dog. The dog fell to the ground.

As festival goers gathered around and began yelling at officer, a K9 officer attempted to give first aid to the dog. The dog was taken to an animal hospital, where it was euthanized after resuscitation efforts failed.

The dog's remains were returned to its owner.

The shooting is under investigation by an independent investigator.

The dog's death is the latest trouble at the Rainbow Gathering. The forest service has called the festival "unauthorized" and "unsactioned." As of Tuesday, officers arrested 8 people and handed out 192 warning notices and 47 violation notices.

The event is organized by the Rainbow Family of Living Light, a group that gathers from around the nation in different locations each year.

The group did not apply for a permit, which is required for groups larger than 75 people. The Forest Service has created a list of regulations and shared it with the group.

Staff writer Grant Butler contributed to this report.

— Samantha Matsumoto

503-294-4001; @SMatsumoto55