The demonstrators began aggressively provoking Turkish-American citizens who had peacefully assembled to greet the President.
Turkey's President Recep Tayyip Erdogan delivers a statement to reporters alongside U.S President Donald Trump after their meeting at the White House in Washington, U.S. May 16, 2017.
The Turkish newspaper Hurriyet reports that Turkish prosecutors are accusing Brunson of "delivering sermons to the Kurds with "a special objective, '" implying that he expressed support for Kurdish separatism or the Kurdistan Workers" Party (PKK), a USA -designated Marxist terrorist group against which Turkey is now waging a military campaign in the southeast of the country.
At their meeting Tuesday, Trump said the USA would re-establish its military and economic partnership with Turkey, committing to backing Turkey's defense against both Islamic State and the PKK.
McCain, the chairman of the Armed Services Committee, and Feinstein, the ranking member of the Senate Committee on the Judiciary, write in the letter to Erdogan that members of the Turkish security detail "allegedly broke through police lines and violently attacked a small group of protesters...wounding at least nine people".
The incident occurred after Erdogan arrived after a White House meeting with President Trump.
Police said 11 people were injured, including a Washington police officer, and two people were arrested for assault. Witnesses reportedly said that the protesters were demanding that a pro-Kurdish lawmaker, Selahattin Demirtas, be released from prison in Turkey.
Trump to take first official direct flight from Saudi to Israel
The kingdom's control of the holy sites has been criticized by Muslims around the world. Last year, President Barack Obama received a less than warm welcome in Saudi Arabia.
The Turkish Embassy also released a statement regarding the violence on Thursday.
A video posted online showed men in dark suits chasing anti-government protesters and punching and kicking them as police intervened.
It was unclear if they were members of Mr Erdogan's security or protesters. Nor did they answer whether or not the Turkish personnel involved in the attack would be disciplined.
"We are already telling you in advance: Our rules of engagement give us this authority", Erdogan said.
On Thursday, Erdogan, speaking in Istanbul, reiterated the warning, saying that "we won't discuss it or consult with anyone", according to the Associated Press.
Such violence is never an appropriate response to free speech and peaceful protest.
The Trump administration hasn't commented on the violence, which was videotaped.
"We respect those concerns, and continue regular consultations with our North Atlantic Treaty Organisation ally on this and other topics of mutual importance", Nauert said.