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WASHINGTON — Bodyguards belonging to the Turkish president's security detail were involved in Tuesday's mass brawl outside the Turkish ambassador's residence here, senior U.S. officials confirmed to NBC News.

The well-dressed guards in suits and ties were captured on social media purportedly showing protesters being kicked and bloodied as uniformed authorities tried to contain the flaring violence. Nine people were hurt and two others were arrested, police said Wednesday, although none of those detained were guards — raising questions about their impunity under the law.

The State Department said in a statement Wednesday that the U.S. was "communicating our concern to the Turkish government in the strongest possible terms."

"Violence is never an appropriate response to free speech, and we support the rights of people everywhere to free expression and peaceful protest," said spokeswoman Heather Nauert.

Meanwhile, the Turkish government blamed the protesters, whom they said — without providing evidence — were affiliated with "terrorist" groups.

"The violence and injuries were the result of this unpermitted, provocative demonstration," read a statement from the Turkish embassy. "We hope that, in the future, appropriate measures will be taken to ensure that similar provocative actions causing harm and violence do not occur."

Emergency personnel were called to the ambassador's residence on upscale Embassy Row — only blocks from the homes of former President Barack Obama, Jared Kushner and Ivanka Trump, and Secretary of State Rex Tillerson — at about 4:30 p.m.

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President Donald Trump had met with his Turkish counterpart, Recep Tayyip Erdogan, at the White House just hours earlier.

Related: Trump and Erdogan Meet Amid Tensions Over Arming Kurds in Syria

A photojournalist for the local CBS affiliate tweeted that the gathering appeared to be made up of pro-Turkey demonstrators. But the event devolved into chaos when someone was reportedly seen carrying a flag of the Kurdish Democratic Union Party in Syria linked to a group that the United States wants to arm — over the objections of Turkey. The Turkish government considers them to be an offshoot of the terrorist organization the Kurdistan Workers Party.

D.C.'s Metropolitan police in a tweet condemned the fighting as standing "in contrast to the First Amendment rights and principles we work tirelessly to protect each and every day." Police officials said they plan to pursue all charges and find others involved.

Erdogan, meanwhile, has been accused of cracking down on journalists and his opposition following a coup attempt last summer that led the Turkish strongman to tighten his grip on power.

Violent clashes broke out between protesters and supporters of Turkey's President Tayyip Erdogan outside the Turkish ambassador's residence in Washington. VOA

Two of those hurt in Tuesday's fracas were seriously injured and taken to the hospital by ambulance, emergency personnel told NBC News.

In footage distributed by international broadcast outlet Voice of America, one man with a bullhorn could be seen on the ground getting kicked repeatedly, including by someone in a suit. Blood dripped down his face.

A separate tweet from a Washington-based Kurdish affairs analyst appeared to show a man in a suit grabbing a woman from behind with his arm around her neck.

The melee prompted Samantha Power, the former U.S. ambassador to the United Nations under Obama, to tweet Tuesday that "clearly Erdogan's guards feel complete impunity, drawing on tools of repression they use at home & knowing he has their back, no matter what."

Clearly Erdogan's guards feel complete impunity, drawing on tools of repression they use at home & knowing he has their back,no matter what https://t.co/jq1tFHwv35 — Samantha Power (@SamanthaJPower) May 17, 2017

D.C. Mayor Muriel Bowser said in a statement that such a "violent attack on a peaceful demonstration — is an affront to DC values and our rights as Americans."

But the Turkish state-run Anadolu news agency blamed local police for being unable to quell the violence and said the guards were merely responding to "terrorist" sympathizers.

Those guards aren't likely to suffer from any fallout, according to Joseph Giacalone, a retired New York Police Department sergeant and professor at John Jay College of Criminal Justice in New York.

Opponents of President of Turkey Recep Tayyip Erdogan rally in Lafayette Park as Erdogan met with and President Donald Trump at the White House in Washington on May 16, 2017. Shawn Thew / EPA

Foreign security details are protected under diplomatic immunity afforded to their countries' leaders, he said. If protesters feel as if their civil rights were trampled, he added, they don't have any meaningful recourse under international law.

"It's going nowhere," Giacalone told NBC News. "This is not American police. There's no Civilian Complaint Review Board. (Protesters) can cry or scream, but the guards are covered."

Embassy properties, he added, also aren't technically under the jurisdiction of the United States. It's unclear how much of the altercation outside of the Turkish ambassador's residence took place on embassy property.

"Americans need to understand that these guys are used to dealing with radicals in their own countries and getting away with it," Giacalone said. "They don't play."