Turkish authorities detained 17 members of a political organization after protesters put a hood over the head of a U.S. Navy civilian in Istanbul.
Youth Union of Turkey, also known as TGB, posted a photo Tuesday to two Twitter accounts, and in one post, the group claimed to have put a "sack on the head of an American soldier."
In a statement, the Istanbul governor's office said the 17 people detained had targeted a civilian employee of a U.S. Navy ship that "came to our city as part of a port visit," according to Reuters.
USS Mount Whitney, the U.S. 6th Fleet's flagship, arrived in Istanbul on Monday and entered the Black Sea on Thursday to join the destroyer USS Porter.
In addition to putting the hood on the civilian's head, the group also chanted "you are our enemy, and you are not wanted here. ... Yankee go home," Reuters reported.
U.S. 6th Fleet didn't comment Thursday on the incident. At a media briefing Wednesday, Defense Department spokesman John Kirby thanked Turkey for its swift action and responsiveness. He referred further questions to Turkish authorities.
The U.S. and other NATO members and partners routinely conduct military exercises in the Black Sea.
Personnel from Naval Striking and Support Forces NATO and 6th Fleet, both under the command of Vice Adm. Gene Black III, were aboard USS Mount Whitney, 6th Fleet said in an Oct. 29 statement.
On Wednesday, the ship hosted a reception that included the U.S. ambassador to Turkey and various Turkish dignitaries, according to 6th Fleet. Black spoke at the reception.
"It is very important to be here and to deepen our maritime cooperation. Turkey is a very valuable NATO ally," he said. "Achieving economic prosperity in the Black Sea region depends on the stability to be achieved at sea."
This isn't the first time TGB has protested the U.S. by putting hoods over Americans' heads.
In 2014, it attacked a group of service members from the destroyer USS Ross who were dressed in civilian clothes. The protesters threw red paint on at least one service member and put a plastic sack over his head, calling him a murderer, the pro-government Turkish newspaper Daily Sabah reported.
The newspaper said putting hoods on U.S. service members is viewed as revenge for a 2003 incident in Iraq, in which U.S. military personnel detained and put hoods on Turkish soldiers operating as part of a special operations team.
U.S. officials had accused the soldiers of plotting to kill an American-backed Iraqi official, The New York Times reported at the time.
On its English-language website, TGB says it stands up for a secular and populist Turkey. The group says it "was founded in order to unite Turkish youth -- ignoring whether they're leftists or rightists -- to defend the motherland."