A passenger ferry sank off the coast of South Korea on Wednesday morning, leaving hundreds missing and at least six people dead. The ship flipped flipped while sinking, possibly trapping hundreds of passengers inside.

According to a report from The Korea Herald, the ferry sank off the coast of South Korea’s Jindo Island south of the country’s mainland. The incident took place just before 9 am.

The ferry was reportedly carrying 462 passengers at the time of the incident. As many as 324 of those passengers were students from Danwon High School that had traveled to Jejudo Island as part of a school field trip.

Six of those passengers, including a young woman, a high school student, and a ferry company worker, have died. According to the Herald, 281 of the passengers are still unaccounted for as of 1 am local time on Thursday.

According to the Herald, South Korean President Park Geun-hye personally visited the central response center in charge of rescue operations. In a statement the President said that a thorough search of the ship will be conducted to ensure no passengers are left inside.

The South Korean Navy, Coast Guard, Air Force, and Army all coordinated rescue efforts at the scene of the sinking. Helicopters and divers are now being used to search the ship for passengers. A U.S. Navy ship has also joined the South Korean rescue efforts, which were initially difficult due to strong currents in the area.

A rescue worker quoted by the Herald has stated that passengers still inside the ship are “unlikely” to have survived due to a combination of cold water temperatures, the current depth of the ship, and the time that has passed since the sinking.

The tragedy has mobilized an outpouring of grief over social media networks. The hashtag #PrayForSouthKorea is now trending worldwide on Twitter.

Image via NDN