Three U.S. sailors were shown on video being attacked and “sacked” by Turkish youths in Istanbul Wednesday. The three servicemen, who have not yet been identified, were in civilian clothes and were grabbed and had hoods placed on their heads by young men carrying the banner of a Turkish nationalist group, the Youth Union of Turkey.

The men targeted are believed to be sailors who were aboard the USS Ross, a warship docked in Istanbul after NATO training exercises in the Black Sea, Bloomberg Businessweek reported. “The video showing an assault on three visiting American sailors is appalling,” the U.S. Embassy in Ankara said via Twitter. “While we respect the right to peaceful protest and freedom of expression, we have no doubt the vast majority of Turks would join us in rejecting an action that so disrespects Turkey’s reputation for hospitality.”

The group of assailants threw packets of red paint at the sailors after grabbing them and then put sacks over their heads. The three sailors removed the bags and ran away from the group.

The unidentified sailors in civilian clothes were walking in Eminönü, a central district of Istanbul, according to a local media report. Activists from the TGB approached one of them and asked whether he was with the sailors aboard the USS Ross. When he said he was, the group descended on him and began the attack.

"U.S. Navy officials are working with the embassy and NCIS to investigate the incident. The three sailors were unharmed and are safely back aboard. They did not require medical attention," Capt. Greg Hicks, a spokesman with U.S. European Command, told CNN.

The group held up TGB banners as well as Turkish flags and called the sailors “murderers” and “killers” during the incident. After the three sailors fled, the group chanted, "Yankee, go home." The group said it is protesting "American imperialism" in Turkey.