A collision between two U.S. Navy ships operating in the Atlantic resulted in no injuries and only minor damage to the ships. According to a report from the U.S. Naval Institute (USNI), the incident occurred on Tuesday, February 5, just after 4 p.m. EST while the two vessels were completing a resupply and refueling-at-sea operation, known formally as an underway replenishment (UNREP). During the operation, the sterns (back ends) of the two vessels—the guided missile cruiser USS Leyte Gulf and the dry cargo ship USNS Robert E Perry—brushed against each other, causing damage to some of the deck equipment on board the Leyte Gulf and to the hull of the Robert E Perry.

“No personnel were injured when a U.S. Navy guided-missile cruiser and dry cargo ship made contact during an underway replenishment off the southeastern coast of the United States, Feb. 5,” the U.S. Navy wrote in a press release.

The incident is currently being investigated by U.S. Fleet Forces Command and Military Sealift Command (MSC), and the ships are currently making their way back to port for further inspection. The USS Leyte Gulf is currently attached to the Abraham Lincoln Carrier Strike Group, which, according to the USNI, is currently conducting a training exercise in the Atlantic. The current training mission is designed to prepare the entire strike group for a wartime deployment, and all of the group’s assets will be tested.

Although the damage to both ships appears to be superficial, UNREP operations are extremely dangerous. In 2012 the USS Essex collided with the USNS Yukon, a replenishment oiler, while the pair were conducting an UNREP in the Pacific near California. Although no sailors were hurt in the incident and neither vessel received serious damage, the Navy fired the Essex commander “due to loss of confidence in his ability to command,” according to a report from Maritime Executive.