BOSTON -- Bystanders and lifeguards rescued two teens who nearly drowned in waters off Mothers Rest pier on Tuesday night in South Boston.

Boston police received an emergency call shortly after 4:30 p.m. Tuesday about people struggling in an area of the water that's not marked for public swimming.

Lifeguards from nearby Carson Beach joined bystanders in the efforts to pull the girls from the water. They pulled from the water a girl who was then transported to Boston Medical Center. Her condition was not immediately known.

The Boston Police Dive Team entered the waters after a search for a second girl who could not be found.

Divers pulled a 13-year-old girl from the water at about 5 p.m. and paramedics transported her to Boston Medical Center, where she was last reported in serious condition.

Authorities did not immediately release the girls' identities as the incident remains under investigation.

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