The U.S. Coast Guard had to escort a cruise ship back to shore after a melee broke out among its passengers in international waters.

Officials said the fight, which involved up to 60 people, erupted around 2 a.m. on a Carnival cruise ship bound for New York.

Theresa James, a travel agent who reportedly witnessed the brawl, told FOX News the initial argument stemmed from allegations of cheating involving a threesome that apparently happened on the ship. James said beer bottles were smashed and people were cut as the confrontation dragged on for about an hour. 

The cruise ship ultimately landed in Manhattan as scheduled after security broke up the fight. 

"Last night while Carnival Magic was returning to New York, a number of guests were involved in an altercation in a nightclub," Carnival said in a statement. "Thankfully no serious injuries were reported and our onboard security team intervened. The ship arrived as scheduled this morning and shoreside law enforcement authorities were notified and met the ship to interview suspects and witnesses and conduct an investigation."

It's unclear whether anyone is facing charges.