COLUMBUS, Ohio (AP) -- Officials at the Columbus zoo say two men were taken into police custody after a zoo employee saw the intruders walking through the facility's North American animal section.

A statement from the zoo said the employee spotted the men at about 1:15 a.m. Friday morning. She called out to them. And when they didn't respond, she notified security.

The zoo said the Delaware County Sheriff's Department assisted with the search for the men, which included multiple officers as well as a helicopter.

Zoo officials say the animals were unharmed, and there does not appear to be any property damage.

The Columbus zoo is home to more than 9,000 animals. The facility hosts more than two million visitors a year.

Additional details weren't immediately available.