Turkey summoned the U.S ambassador on Monday to protest the treatment of Turkish security officials in the United States during a visit by President Tayyip Erdogan last week, the foreign ministry said.

A brawl erupted between protesters and Turkish security personnel outside the Turkish ambassador’s residence during Erdogan’s visit to Washington to meet U.S. President Donald Trump.

Turkey blamed the violence on demonstrators linked to the militant Kurdistan Workers Party while Washington’s police chief described the incident as a “brutal attack” on peaceful protesters.

The U.S. State Department said in a statement the conduct of Turkish security personnel during the incident was “deeply disturbing.” It confirmed the U.S. ambassador in Ankara had been summoned by the Turkish government to discuss the “violent incidents.”

The Turkish foreign ministry said it summoned the U.S. ambassador to protest “aggressive and unprofessional actions” by U.S. security personnel to the security team of Turkish Foreign Minister Mevlut Cavusoglu.

“It has been formally requested that the U.S. authorities conduct a full investigation of this diplomatic incident and provide the necessary explanation,” the foreign ministry said in a statement.

It said that lapses of security experienced during Erdogan’s stay in Washington were caused “by the inability of U.S. authorities to take sufficient precautions at every stage of the official program,” adding that incidents would not overshadow what was otherwise a “very successful” visit.

Police have said 11 people were injured, including a Washington police officer, and two people were arrested for assault. At least one of those arrested was a protester.

Washington said last week it was voicing its strongest possible concern to Turkey over the brawl. U.S. Senator John McCain, one of the leading foreign policy voices in Congress, on Thursday called for the expulsion of Turkey’s U.S. ambassador.