KUALA LUMPUR (Reuters) - Nine crew members of a Malaysian navy boat are missing after they lost contact with their parent ship while chasing away intruding fishermen, the navy said on Monday.

The nine were part of a boarding team from the warship KD Perdana, on patrol off the south coast, the Royal Malaysian Navy said in a statement.

The team was chasing several foreign fishing boats out of Malaysian waters when contact was lost on Saturday evening.

A search-and-rescue operation was launched about an hour later, after the KD Perdana failed to find the boat, the navy said.

Eleven ships and two aircraft had been deployed for the search, it said.

Southern Malaysian waterways, which border Indonesia and Singapore, include busy international shipping lanes and rich fishing grounds.

Overloaded migrant boats also ply the waters and occasionally run into trouble.