The Hong Kong government’s air support service said 27 people were missing after their ship was cut in half by a typhoon in the South China Sea on Saturday.

The engineering ship was 160 nautical miles southwest of Hong Kong when it got caught up in Storm Chapa. The Hong Kong government’s aviation service said it had “severely damaged and split into two”.

Aid was dispatched to the scene after being notified at around 7:25 am local time (2325 GMT Friday).

Authorities said three of the 30 crew members were rescued at 3 p.m. local time and taken to hospital.

Footage provided by Hong Kong authorities shows a person being airlifted as waves crash onto the deck of the half-submerged ship.

A Hong Kong government statement said that, according to the three survivors, the other crew members may have been swept away by waves before the first helicopter arrived.

Typhoon Chaba formed in the middle of the South China Sea and made landfall Saturday afternoon in south China’s Guangdong Province.

The authorities said that the ship’s site recorded winds of 144 kilometers per hour and waves 10 meters high.

Rescuers will expand the search area “due to the large number of missing persons” and extend the operation until night if conditions permit.