A Polaris employee testing a snowmobile for the Minnesota company collided with a sled dog team in Alaska this week along a highway near Denali National Park and Preserve, killing three competitive racing dogs.

No humans were hurt, but two other dogs also were injured in the Monday crash, according to the Alaska State Troopers and the kennel owner. The troopers are investigating the incident but said Tuesday they had not arrested anyone or issued any citations and said alcohol does not appear to be a factor.

The driver, who the Anchorage Daily News reported is a Minnesota man, stopped to render aid.

Jess Rogers, a spokesperson for Polaris, said the company is cooperating with local law enforcement and conducting an internal investigation. So far, Rogers said the investigation has found the employee was following the company's safe riding protocols, including operating "at an appropriate speed."

The company would not confirm information about the driver.

"We want to express our deep sympathies to the family that lost three of their beloved sled dogs," Rogers said.

Polaris tests its snowmobiles at its Roseau facility but also in other parts of the world — including Alaska — since the 1960s. Rogers described the riders as experts and said the company is not aware of any other collisions involving snowmobile test riders and sled dog teams.

The test team has to meet training requirements and follow safety protocols. Last year, the test team put more than 200,000 miles on test sleds, Rogers said.

The crash happened along the Denali Highway, near the city of Cantwell. The three dogs killed were named John Lennon, Buttercup and Solo, said Jim Lanier, who runs Northern Whites Kennel in Chugiak near Anchorage. The injured dogs are named KitKat and Leia.

Mike Parker wrote on Facebook that he was mushing a dog team for Lanier after competing in a race when the team had a head-on collision with the snowmobile. The driver was in a group that had passed the sled dog team "many, many times over the weekend" before the crash, Parker wrote. He wrote that he has been working toward an Iditarod run and is planning to complete a final required qualifying race this season.

"This was an unspeakable tragedy," Parker wrote. "Myself, Jim, our families and the mushing community are mourning the loss of these wonderful animals. ... Words cannot describe how important and meaningful these animals are to me and the Laniers."

Lanier, who is originally from Fargo but moved to Alaska in the 1960s, said Friday the three dogs killed had run in the Iditarod, which he has raced 21 times.

Three-year old Solo survived a few hours while they sought medical care before dying in his arms, he said.

"That particular dog was not only the best sled dog I've ever had and the best leader sled dog, it was our family pet," Lanier said. "It slept with my wife and me."