Coast guard officials in the Philippines say a Chinese navy helicopter harassed their country's fishing boats in the South China Sea. They say the incident happened inside Manila's exclusive economic zone.

The officials say the chopper buzzed the vessels Wednesday near a shallow seabed off the Spratly Islands, approaching as close as 5 meters. The wooden boats were rocked by the rotor wash, but not harmed.

The coast guard dispatched two patrol ships provided by Japan to step up vigilance in the area.

Philippine Coast Guard Spokesperson Jay Tarriela said, "As the security forces, we are committed to ensuring that our Filipino fishermen are safe."

Last year, Philippine authorities spotted a flotilla of Chinese vessels docked in the area.

China's foreign ministry says Beijing has undisputed sovereignty over the islands. It says any actions to protect its rights in nearby waters are legal.