A cruise ship with a reported nearly 300 passengers has been quarantined in the Caribbean port of St. Lucia since Monday morning after a crew member onboard was confirmed to have the measles.

Health officials in St. Lucia decided to issue the quarantine after "reputable sources" revealed someone on the ship had the measles, reports CNN. St. Lucian authorities have been in contact with the Pan American Health Organization and the Caribbean Public Health Agency to aid in handling the situation. 

Island health officials haven’t released the name of the ship, but a St. Lucia Coast Guard told NBC News that the ship was named “Freewinds,” which is the name of a cruise ship privately owned and operated by the Church of Scientology.

Dr. Merlene Fredericks-James, St. Lucia’s chief medical officer, issued a statement Wednesday to clarify the situation and the crew member’s condition. She said that given the confinement on the ship, it’s possible other people onboard were exposed to the virus. “The ship’s doctor has the confirmed case in isolation on the ship. The individual is in stable condition,” Fredericks-James said.

The ship is still under quarantine and no one has been allowed to leave. However, island authorities have also said they don’t have the power to hold the ship in port. It is currently scheduled to depart St. Lucia at 11:59 p.m. Thursday.