A four-year-old boy is reported to be in a critical condition after almost drowning in a cruise ship wave pool.

The youngster was ‘swept under’ while swimming in the pool on Royal Caribbean’s Oasis of the Seas off the coast of Florida, and is believed to have been submerged for between five and 10 minutes.

He was initially treated by the ship’s onboard medical staff before the ship altered course and transported him to the Broward Health Medical Centre in Fort Lauderdale in Florida.

The vessel was an hour into its journey the incident took place. A passenger on the deck alerted another swimmer when they noticed the child was under the water.

They then grabbed the boy from underneath and dragged him out of the pool unconscious before medics began CPR.

The ship departed from Port Everglades approximately an hour before the wave-pool emergency happened.

A Royal Caribbean spokeswoman confirmed to the local Sun-Sentinel that the boy from Italy “was rescued from one of the ship’s swimming pools.”

The boy, who has yet to be named, was travelling with his two parents and siblings.

The spokeswoman said the ship’s care team were providing support for the family and their “thoughts and prayers were with them”.