A woman reported being grabbed from behind while walking in a park east of Mankato and sexually assaulted by a man with a weapon, authorities said Thursday. No arrest has been made.

The woman said the attack occurred shortly after 5:30 p.m. on July 6 on a trail in Wildwood Park, located in LeRay Township between Eagle Lake and St. Clair.

She said the man was armed, possibly with a knife, according to the Blue Earth County Sheriff’s Office. The woman did not offer a specific description of the man.