SINGAPORE - The Singapore Civil Defence Force (SCDF) has called off an underwater search operation more than three hours after it responded to a suspected drowning incident at Sentosa's Palawan Beach.

SCDF said it was alerted to the case at 2.50pm on Thursday (Sept 7).

It dispatched two fire engines, a marine vessel, an ambulance and officers from its Disaster Assistance and Rescue Team (DART).

DART officers conducted an underwater search operation at a depth of about 4m in low visibility.

"As there was no sign of a case, the underwater search operation was called off at 6.30pm," said SCDF. "A periodic surface search will be conducted henceforth," it added.

A spokesman for Sentosa Development Corporation told ST that Sentosa's beach patrol officers responded to a request for assistance from a member of the public at Palawan Beach at about 2.30pm on Thursday.

"Sentosa Rangers also alerted the Singapore Civil Defence Force and Singapore Police Force, who have arrived onsite to render further assistance," said the spokesman.

The Straits Times understands that eyewitnesses saw a pair of hands waving in the water, and heard someone shouting for help.

ST has contacted the police for more information.