Federal Aviation Administration spokeswoman Laura Brown said Flight 1549 had just taken off from LaGuardia Airport en route to Charlotte, N.C., when the crash occurred in the river near 48th Street in midtown Manhattan.
The plane, an Airbus 320, took off at 3:26 p.m. and went down minutes later, Brown said.
"There were eyewitness reports the plane may have flown into a flock of birds," Brown said. She added, "Right now we don't have any indication this was anything other than an accident."
The plane was submerged in the icy waters up to the windows when rescuers in Coast Guard vessels and ferry boats arrived, opened the door and pulled passengers in yellow life vests from the aircraft, whose fuselage appeared intact. The plane eventually sank in the near-freezing water on one of the coldest days of the year, with the mercury around 20 degrees.
Witnesses said the plane's pilot appeared to guide the plane down.
"I see a commercial airliner coming down, looking like it's landing right in the water," said Bob Read, who saw it from his office at the television newsmagazine "Inside Edition." ''This looked like a controlled descent."
Barbara Sambriski, a researcher at The Associated Press, saw the plane go down from the news organization's high-rise office. "I just thought, 'Why is it so low?' And, splash, it hit the water," she said.
Joe Mazzone, a retired Delta Air Lines pilot, said it is not unusual for birds to strike planes. In fact, he said, when planes get ready to take off, if there are birds in the area, the tower will alert the crew.
"They literally just choke out the engine and it quits," Mazzone said.
Twenty-seven years ago this week, an Air Florida plane bound for Tampa crashed into the Potomac River after hitting a bridge just after takeoff from Washington National Airport. The crash on Jan. 13, 1982, killed 78 people including four people in their cars on the bridge. Five people on the plane survived.
On Dec. 20, a Continental Airlines plane veered off a runway and slid into a snowy field at the Denver airport, injuring 38 people. That was the first major crash of a commercial airliner in the United States since Aug. 27, 2006, when 49 people were killed after a Comair jetliner mistakenly took off from the wrong runway in Lexington, Ky.