Rescue teams continue their desperate search in a New York City river for a missing teenager who hasn't been seen since Friday afternoon.

Witnesses told police they saw a boy jump into East River around 4 p.m. Friday at East River Park near East 6th Street in the East Village, according to Fox 5 NYC.

As of 9:30 a.m. Saturday, there is still no sign of the missing boy, according to police, who said that he is 13 years old but didn't release any other information.

Water rescue teams, helicopters and emergency personnel have been searching all night and into the morning.

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Investigators don't know why the boy went into water, but foul play isn't suspected, as of Saturday morning, according to CBS News. 

The boy lives in the neighborhood, ABC 7 reported. 

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The East River is a 16-mile-long waterway that connects Upper New York Bay with the Long Island Sound and separates Manhattan from Brooklyn and Queens.