WOODSTOCK, Ga. (AP) — Crews are searching for a missing swimmer in a river north of Atlanta.

The search and rescue operation was underway Tuesday morning for the 26-year-old woman at Rope Mill Park in the Woodstock area, WSB-TV reported. She went for a swim in Little River, which winds its way through the park, and hasn’t been seen since then, authorities said.

Woodstock police, firefighters and other agencies have been looking for her since before dawn Tuesday. Police have urged people to avoid the area until further notice.