By Rebecca Shabad - 04/16/14 07:12 AM EDT
A U.S. Navy amphibious assault ship is heading toward the site where a South Korean ferry carrying 459 people sank Wednesday morning, Stars and Stripes reports.
At least four people were confirmed dead and 55 were injured, according to the Associated Press. Nearly 300 people are reportedly missing. Most of the passengers were high school students.
On Wednesday morning, a rescue operation involving 160 coast guard and navy divers was underway to find survivors inside the ship’s wreckage or in the water.
A large number of the missing might be trapped in the ship or floating in the ocean, the AP reports.
The event could be South Korea’s biggest ferry disaster since 1993, when 292 people died.