As the violence broke out, videos from the confrontation quickly spread on social media showing Erdogan's bodyguards pummeling people, even kicking people in the face.
The U.S. State Department has also expressed its official concern "in the strongest possible terms".
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Witnesses described what happened at the scene. "Somebody told them to go and beat up on these peaceful demonstrators and I think it should have repercussions, including identifying these people and bringing charges against them". He held me and threatened to kill me. "Someone was beating me in the head nonstop, and I thought, 'Okay, I'm on the ground already, what is the goal to beat me?" "We are telling you this now in advance", Erdogan said. "We would just take the step".
The US agrees with Turkey in designating the PKK as a terrorist organization, but rejects the idea that Kurdish forces in Syria or Iraq should be treated in the same fashion.
President Donald Trump, accompanied byTurkish President Recep Tayyip Erdogan, speaks in the Roosevelt Room of the White House in Washington Tuesday, May 16, 2017.
Sen. Claire McCaskill, D-Mo., joined in on Twitter, calling the violence "unacceptable" and echoing McCain's demand that the ambassador be sent back to Turkey.
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John McCain (R - AZ) is demanding the USA throw Turkey's Ambassador "the hell out of the United States of America" after security working for Turkey's president attacked American protesters.
Washington and Ankara are bitterly at odds over United States support for the Kurdish People's Protection Units (YPG) in Syria, which Turkey considers a front for banned Kurdistan Workers' Party (PKK) separatists.
U.S. expresses concern in "strongest possible terms" after violence erupted outside the Turkish embassy.
Erdogan also said that the USA had made up its mind on Raqa, which meant Turkey could not join the operation "under the current circumstances", referring to the YPG's involvement. Senator John McCain, R-AZ, and Senator Claire McCaskill, D-MO, both called for the expulsion of Turkey's ambassador.
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Wainwright said the agency is analyzing the virus and has yet to identify who is responsible for the attack. She said: "We were instructed by the CCG to turn all computers off on Friday afternoon".
Erdogan said that the United States had made its decision on the subject of the Raqqa operation and that Turkey could not participate, given the YPG involvement. "This kind of thing can not go un-responded to diplomatically", Senator John McCain told MSNBC's Morning Joe programme on Thursday.