SEOUL, South Korea — At least nine people were killed and 14 others injured Sunday after being swept away by a sudden large wave that crashed over a breakwater on South Korea's west coast, the Coast Guard said.

The wave — believed to have been as high as 16 feet — slammed over the breakwater near a beach southwest of Seoul where dozens of people had been fishing and sightseeing, said Lee Won-il, a local Korea Coast Guard officer.

Lee earlier said up to 15 people were believed to be missing. By late Sunday it appeared that those who had been reported missing were accounted for, but Lee said officials were continuing search operations as a precaution.

The dead included two children aged 9 and 5, and two of the injured, including another 9-year-old, were in critical condition, Lee said.

Witnesses described scenes of grief and panic after the wave washed over the breakwater at Daecheon Beach in the city of Boryeong some 120 miles southwest of Seoul.

"All of a sudden, there was a sound of thunder and lightning and then people screaming," Ko Myung-rae, the owner of a restaurant in the area, was quoted as saying by Yonhap news agency.

"As I went out, children were crying, saying 'Our mother died,"' he said. "As I looked at the sea, I saw people floating there."

Thirty-six Coast Guard, navy and private fishing boats and 25 scuba divers were participating in the search, while about 200 Coast Guard and fire department personnel and government officials were helping on shore, Lee said. They planned to work through the night.

South Korea's weather agency had forecast there would be strong winds and high waves in the area but did not issue any advisory, Lee said.

The wave was believed to have been caused by regular tidal movements in the Yellow Sea, he said, adding that it had been cloudy and drizzly when the incident happened.