SHANGHAI, April 12 (Xinhua) -- One person is missing after a helicopter from China's Antarctic exploration ship, Xuelong, crashed into the East China Sea off Shanghai Sunday.
Four people were aboard the helicopter when it crashed near the estuary of the Yangtze River at about 11:20 a.m., said a spokesman for the China Marine Search and Rescue Center.
Three were rescued, the spokesman said.
The center has dispatched three rescue boats to search the missing person, he said.
The ship-based helicopter, which was rented by the Xuelong, or "Snow Dragon," had sunk, and rescuers were trying to locate it, he said.
The Xuelong just arrived at a Shanghai dock. The helicopter crashed just a minute after taking off from the vessel, he added.
The cause of the accident is still unknown.
Carrying 140 crew, including scientists, technicians and sailors, the Xuelong left Shanghai in October for a 173-day trip, the longest in China's Antarctic expedition history.
The expedition team had successfully erected a new research station at Dome Argus (Dome A), the pole's highest icecap at 4,093meters above sea level.