Fallout continues after a vicious fight outside the Turkish Ambassador's residence at Sheridan Circle Tuesday afternoon.

Washington's police chief Peter Newsham called the fighting apparently "unprovoked" and "very brutal."

He measured his words carefully, recognizing that this has become an international diplomatic incident.

Still, he was clear, this violent melee involving Turkish security guards was out of bounds on U.S. soil.

MORE: Demonstration outside Turkish Ambassador's residence ends with injuries, arrests

Graphic video appeared to show the aggressors were men in dark suits and sunglasses. They brutally beat anti-Turkish government demonstrators who had been protesting peacefully at locations in D.C. throughout the day, as Turkey’s president met with President Trump.

Nine people, including a D.C. police officer were hurt.

The attack happened on American soil—not the grounds of the Turkish Embassy.

A key question now is whether the Turkish security officers are covered by diplomatic immunity.

The State Department issued a statement saying it is "communicating its concern to Turkish government in the strongest possible terms."

So far, the only people arrested were two protestors, who are U.S. The 42-year-old man from Fairfax was charged with assaulting a police officer and a 49-year-old man from New York was charged with aggravated assault.

The Turkish Embassy released this statement Wednesday evening about the incident:

“Groups affiliated with the PKK, which the U.S. and Turkey have designated as a terrorist organization, gathered yesterday without permit in Sheridan Circle in the immediate vicinity of the Ambassador’s Residence, while the President of Turkey was visiting the Residence. The demonstrators began aggressively provoking Turkish-American citizens who had peacefully assembled to greet the President. The Turkish-Americans responded in self-defense and one of them was seriously injured. The violence and injuries were the result of this unpermitted, provocative demonstration. We hope that, in the future, appropriate measures will be taken to ensure that similar provocative actions causing harm and violence do not occur.”