HONOLULU (AP) — After more than 600 acts of vandalism to city parks in three years, Mayor Kirk Caldwell unveiled on Thursday a three-month pilot project to lock up gates and bathrooms.

The increased security began this month. A private security company, American Guard Services Inc., locks the bathrooms and gates at night at city parks that have them, and park employees unlock them each morning.

Caldwell has ordered parks officials to install gates on park bathrooms that don't have them, but that project is complicated because bathroom entrances are not uniform.

Of the nearly 300 parks, more than 210 of them have bathrooms, parks and recreation spokesman Nathan Serota said.

"Some of them have (bathroom) gates and some of them do not," Serota said.

The project announcement follows the installation of security cameras at Sandy Beach, Ala Moana Beach Park and Kaiaka Bay Beach Park on the North Shore. Caldwell said the cameras have proven successful in deterring vandalism.

Since the pilot project to lock up bathrooms and gates at 25 beach parks from Sandy Beach to Aiea began, there have been no acts of vandalism at night during closed hours, said Angela Watson, American Guard's Hawaii branch manager.

The only incident, graffiti at a Sandy Beach bathroom, occurred during the day over Easter weekend, Watson said.

The city is paying American Guard Services $25,916 during the pilot period that runs through June.

"If it makes a difference, and I believe it will, then we'll try to roll it out island wide," Caldwell said.