US police have issued arrest warrants for a dozen Turkish security agents and two others accused of taking part in a violent altercation with protesters on May 16 as Turkey's president visited Washington.
District police chief Peter Newsham said nine agents, three Turkish police officers and two Canadians are being sought. He also said two arrests had been made on Wednesday.
Mr Newsham said: "We all saw the violence that was perpetrated against the protesters. We're not going to tolerate this."
Relations were severely strained even before the melee, which came as Turkish president Recep Tayyip Erdogan arrived at the Turkish ambassador's residence after a White House meeting with US president Donald Trump.
Video footage showed security guards and some Erdogan supporters attacking protesters, leaving nine people hurt.