A 3-year-old boy has drowned at a northern Ohio indoor water park that calls itself the nation's largest.

The boy drowned Sunday in an outdoor pool at Kalahari Resorts water park in Sandusky on Lake Erie. Police and park officials say lifeguards were on duty at the time.

Kalahari spokeswoman Carrie Leum says park employees are "deeply saddened" by the toddler's death. She says the park is cooperating with law enforcement.

The state has taken disciplinary action against Kalahari at least five times since the resort opened in 2005.

Inspectors with the Amusement Ride Safety Division told Kalahari management last May the park had fewer lifeguards than expected and "many water rides were operated in a careless and unsafe manner."

The 173,000-square-foot park features rides such as the Elephant Trunk and the Rippling Rhino.