Tuesday's attack was not the first incident where Erdoagan's security has been involved in violently clashing with protesters.
There may be issues with diplomatic immunity, Police Chief Peter Newsham said at a news conference Wednesday.
The presidents of the United States and Turkey vowed Tuesday to fix a relationship battered by years of disputes over Syria's civil war and its various fighting groups, even as they broached a new disagreement over USA plans to arm Kurdish fighters.
The Turkish Embassy said in a statement the protesters were affiliated with the outlawed PKK.
The guards' release left the US struggling to point to anything that amounts to accountability. "We will continue to work with our partners at the United States State Department and United States Secret Service to identify and hold all subjects accountable for their involvement in the altercation".
Demonstrators were outside the Turkish embassy, calling on President Recep Tayyip Erdogan to end his support for pro-ISIS forces inside Syria and Iraq.
United States extends sanctions relief under Iran nuclear deal
Separately, however, Washington also extended wider sanctions relief for Iran called for under the nuclear accord. But the USA also announced new unrelated sanctions in a bid to show it was not letting Tehran off the hook.
A video posted online showed men in dark suits chasing anti-government protesters and punching and kicking them as police intervened. Another person wrenches a woman's neck and throws her to the ground.
Photos and videos have scoured the internet since the situation occurred and in them you can see the chaos ensue, including men being kicked on the ground and others walking around bleeding from head injuries.
Washington Mayor Muriel Bowser and five Republican senators, including John McCain of Arizona and Marco Rubio of Florida, also condemned the assault.
Another video shared on social media Thursday showed Erdogan watching the melee unfold from the backseat of his vehicle. He later exits the vehicle and peers toward the chaos.
Turkey's embassy blamed the violence on demonstrators, saying they aggressively provoked Turkish-American citizens gathered to see Erdogan.
The White House said after the meeting that Trump raised the incarceration of Pastor Andrew Brunson, an American pastor detained since last October, and asked that the Turkish government expeditiously return him to the United States.
Soundgarden singer Chris Cornell dies
A medical examiner has determined Cornell killed himself by hanging in a room at the MGM Grand hotel in following a concert. On the night before his passing, there seemed to be no clue Chris Cornell's cause of death would be a suspected suicide.
The violent capstone to Erdogan's visit spoke to the sky-high tensions between the USA and Turkey, NATO allies that have increasingly sparred over US strategy toward defeating IS militants in Syria.
To Turkey's dismay, Trump has made a decision to arm Syrian Kurdish militants in the impending fight to retake the key city of Raqqa.
The U.S.is relying on regional allies including Turkey for intelligence-sharing and military assistance as it crafts a Syria policy, particularly as Iran and Russian Federation work to bolster Syrian President Bashar Assad's government.
In its protest against Trump's decision, Turkey's foreign minister demanded Thursday that Trump dismiss the US envoy in charge of the anti-IS coalition, Brett McGurk.
While Mr Erdogan's government had long warned U.S. officials against expanding support for the People's Protection Units (YPG), a group Turkey sees as an existential threat, the warm public remarks from both leaders reflect the North Atlantic Treaty Organisation allies' need to hold together a key partnership at a time of intense strain.
Still, Nauert sought to acknowledge Turkey's misgivings about terrorism by the PKK and other groups.
Lobs are Trending at the Cannes Film Festival
The 31-year-old actress let her long tresses loose, while opting for bold, dark lips and nails to compliment her attire. But Bella's latest sexy stunt at this year's fest just took things to a whole new level.
- Iguodala, Pachulia practice, still questionable for Game 3
- Massive taxpayer loan to fund cleanup of Alberta's dirty, abandoned oil wells
- NBCSN Predators vs. Ducks Game 2 Hockey Sun 4pm PDT
- United States should take some of blame for massive cyberattack, Chinese media says
- UK's May promises voters immigration curbs, fairer society
- Putin Considers How To Serenade Trump At First Meeting
- Atlanta United reschedules 3 games at Mercedes-Benz Stadium
- Tornado touches down in Oklahoma, no injuries reported
- Anything can happen - Tottenham star Alli uncertain of future
- Paul Pierce Thinks Celtics Have To Trade The #1 Overall Pick