TURTLE RIVER, Minn. -- Authorities say two horses and their riders were rescued Saturday after getting stuck in a bog in northern Minnesota.

Two people were riding horses on the Three Island County Park trail system when their horses began to sink into the bog, the Beltrami County Sheriff's Office said. The horses got scared and ran further into the bog before getting stuck.

The riders called 911, and multiple agencies responded. Using wooden boards, authorities made a "floating bridge" for the horses to walk on until they made it to solid ground. The rescue took about four hours in total, the sheriff's office said.