support for Turkish President Recep Tayip Erdoğan outside The White House | Chris Kleponis/AFP via Getty Images DC police charge 12 Turkish security personnel over protest melee Incident comes amid increasingly strained tensions between US and Turkey.

Washington’s Metropolitan Police Department on Thursday announced criminal charges against 12 Turkish security personnel involved in last month’s alleged assault of protesters demonstrating against Turkey’s president during his visit to the district.

Video of the incident in northwest Washington’s Sheridan Circle showed dark-suited men, some carrying holstered guns and wearing earpieces, rushing past a line of police officers and attacking sign-carrying protesters who were gathered nearby the Turkish ambassador’s residence. In a separate video, Turkish President Recep Tayyip Erdoğan could be seen in the driveway of the ambassador’s residence watching the melee for a moment before walking inside.

“You had peaceful demonstrators that were physically assaulted in the District of Columbia,” Metropolitan Police Chief Peter Newsham said. “The message to folks that are going to come to our city, either from another state or another country, is that’s not going to be tolerated in Washington, D.C.”

As of Thursday, a total of 18 arrest warrants have been issued over the incident. Two people were arrested the day of the brawl, and Newsham said two more were arrested earlier this week in Virginia and New Jersey.

Two other suspects, whose charges were announced Thursday alongside the Turkish security personnel, are Canadian citizens, Newsham said.

Whether or not the Turkish citizens, who were all either Turkish security officers or Turkish police officers, will ever actually face charges in the U.S. remains to be seen. Newsham referred all questions regarding extradition to the State Department but said that all of the foreign suspects would be arrested should they ever attempt to enter the United States.

Neither the State Department nor the Turkish Embassy returned requests for comment. In a statement issued in the days after the incident, the State Department said it was “communicating our concern to the Turkish government in the strongest possible terms.”

The 14 foreign suspects announced Thursday were identified with the full cooperation of the State Department, Newsham said, by comparing videos of the incident to passport and visa photos. The chief said his department would circulate additional photos of yet-unidentified suspects who could possible face charges.

The incident comes amid increasingly strained tensions between the U.S. and Turkey, a NATO ally that has grown more authoritarian in recent years under Erdoğan’s leadership and drawn criticism from prominent U.S. politicians. Turkey is also a key U.S. ally in its campaign against Islamic State militants, but the two nations have butted heads over their respective relationships with Kurdish fighters, some of whom the U.S. has armed even though Turkey claims the groups are terrorist organizations.

“In the United States, and particularly in the District of Columbia, we hold our ability to peacefully protest as a sacred right,” Newsham said. “It’s just something we’re not going to tolerate. We have dignitaries that are in and out of this city on a daily basis. Rarely have I seen, in my almost 28 years of policing, the type of thing that I saw in Sheridan Circle on that particular day.”