A tug boat sank in the Tennessee River in north Alabama Sunday morning, spilling between 3,000 and 5,000 gallons of diesel fuel into the water, according to the Florence Police Department’s Facebook page.

Police said the boat sank near the O’Neil Bridge, which spans the Tennessee River next to McFarland Park in Florence. The report said fuel had already begun washing up on the beaches at the park, and police had started getting people to exit the water.

Police warned swimmers to stay out of the water and off the beaches until further notice.