Turkey’s Foreign Ministry lodged a formal protest Monday with the U.S. ambassador over “aggressive” actions by American security personnel during a visit to Washington last week by President Recep Tayyip Erdogan that was marred by a violent clash between Turkish guards and protesters.

The summoning of the ambassador, John Bass, sharply escalated a diplomatic rift between Turkey and the United States following the violence. Footage of the brawl was widely circulated on social media, prompting outrage in the United States, along with calls for the prosecution of the Turkish guards and even the expulsion of Turkey’s ambassador to Washington.

American and Turkish officials have provided directly contrasting versions of how the violence unfolded. Local police said the Turkish guards savagely attacked a peaceful protest outside the Turkish ambassador’s residence as Erdogan was visiting. Footage of the melee showed what appeared to be Turkish security guards kicking and choking protesters as police struggled to contain the unrest. It also showed Erdogan watching, from a distance, as the fighting raged.

Erdogan’s critics seized on the bloody altercation — and a similar flash of violence during the Turkish president’s visit to Washington last year — as indicative of his government’s iron-fisted approach to protests and dissent at home.

But Turkish diplomats faulted the local police, saying they had failed to quell an “unpermitted” and “provocative” demonstration.

(Kareem Fahim, Jason Aldag / The Washington Post)

The Turkish Foreign Ministry’s statement Monday went even further, criticizing “the inability of U.S. authorities to take sufficient precautions at every stage of the official program.” And it demanded that the United States conduct a “full investigation of this diplomatic incident and provide the necessary explanation.”

The statement also blamed “U.S. security personnel” for “aggressive and unprofessional” actions against the Turkish foreign minister’s protective detail. A Turkish official said it was a reference to an incident several hours after the protest, when U.S. diplomatic security agents briefly detained two Turkish guards as they were trying to enter the Turkish Embassy. The guards were later released and returned to Turkey, the official said.

Heather Nauert, a State Department spokeswoman, confirmed in a statement that Bass had been summoned by the Turkish Foreign Ministry “to discuss the violent incidents involving protestors and Turkish security personnel on May 16.”

“As we noted previously, the conduct of Turkish security personnel last week was deeply disturbing,” she said. “The State Department has raised its concerns about those events at the highest levels.”

The spiraling argument appeared to sour what by all accounts had been a friendly meeting between Erdogan and President Trump before the protest. In a joint press appearance at the White House, the two leaders were full of mutual praise and spoke of hopes for a closer and more productive relationship.

But the rift has also laid bare policy disagreements, particularly over the war in Syria, that have stirred tensions between the two allies. Turkey has been angered by the Trump administration’s decision to arm a Kurdish force to fight the Islamic State militant group in Syria in partnership with the United States. Turkey says the group is an affiliate of the Kurdistan Workers’ Party (PKK), which is regarded as a terrorist organization by Ankara and Washington.

Kurdish activists were among the protesters in D.C. on May 16 outside the ambassador’s residence, according to footage of the violence. Some held signs in support of Selahattin Demirtas, a co-leader of a pro-Kurdish political party who is in prison and facing prosecution in Turkey. Others held the flag of the People’s Protection Units, the U.S.-backed Syrian Kurdish force.

It is not clear from the footage what set off the melee, but Turkish security guards, as well as men in suits who were standing among a pro-Erdogan contingent, can be seen attacking the protesters, including repeatedly kicking a man lying on the ground. Another video shows Erdogan himself watching the protest after emerging from his car in the ambassador’s driveway.

Turkey’s semiofficial Anadolu news agency on Saturday published an account by one of its correspondents that said the first fights broke out when the protesters threw water bottles at a pro-Erdogan group.

When the Turkish president arrived at the ambassador’s residence, it said, “protesters continued their grave insults, so some Turkish citizens and the head of the president’s security detail stepped in.”

The tensions stirred by the violence were apparent at a conference on U.S.-Turkey relations held at the Trump hotel in Washington on Monday. Bass, who was listed as a luncheon keynote speaker, did not attend, though it was unclear whether his absence was caused by the diplomatic row.

Turkey’s ambassador to Washington, Serdar Kilic, used his speech at the conference luncheon to defend his country’s actions. “Differences of opinion are natural among two allies,” he said, but added: “There is a big difference between freedom of expression and expression of solidarity with terrorists and terrorism. It was disappointing to see friends of PKK on the streets of Washington, D.C.”

Another speaker, State Department Undersecretary Thomas Shannon, praised Turkey’s longtime alliance with the United States as well as the resolve of Turkish citizens in responding to the coup attempt last year. “That is why Americans were so concerned and disturbed by the violent incident,” he said.

One of the conference chairs, Ekim Alptekin, a Turkish businessman who is close to senior Turkish officials, was at the center of another recent controversy between the United States and Turkey when it emerged that a company Alptekin owned had paid former national security adviser Michael Flynn to investigate an enemy of the Turkish government.

Carol Morello and Tom Hamburger in Washington contributed to this report.

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Erdogan’s guards clash with protesters outside Turkish ambassador’s D.C. residence

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