CNN  — 

Authorities are investigating after a 10-year-old girl drowned on a cruise ship off the coast of Myrtle Beach, South Carolina.

The medical team aboard the Norwegian Gem tried to revive the girl after she was reported unresponsive on the ship’s pool deck Sunday afternoon, Norwegian Cruise Line spokeswoman Vanessa Picariello said in a statement.

“After extensive efforts, the guest could not be revived,” she said. “We extend our deepest sympathies to the family during this very difficult time. Norwegian’s care team is providing full assistance and support to the family.”

The ship left New York on Saturday on a seven-day cruise to Florida and the Bahamas, Picariello said.

The girl drowned when the ship was about 75 miles east of Myrtle Beach, U.S. Coast Guard Petty Officer 2nd Class Nate Littlejohn said. Coast Guard investigators boarded the ship Monday, he said.

About 10 people die daily from unintentional drowning in the United States, making it the fifth-leading cause of unintentional injury death, according to the Centers for Disease Control and Prevention. About 20% are under age 14.