Parks Department officials are warning beachgoers to be careful swimming when there are rip currents.

Authorities suspect a rip current pulled a Brooklyn teenager under the water last week, causing him to drown. Parks Department officials say there haven't been frequent strong rip currents off Brooklyn beaches, but swimmers who encounter them should swim parallel to the shore until the current has passed. They also advise swimmers to tread water or float with the current.

Beachgoers should never swim without on-duty lifeguards present, officials say.