WASHINGTON -- Police in the U.S. capital issued arrest warrants Thursday for a dozen Turkish security agents accused of attacking protesters during a visit by President Recep Tayyip Erdogan last month, prompting an angry denunciation by Turkey's leader and creating a new spat between the NATO allies.

Secretary of State Rex Tillerson said the charges "send a clear message that the United States does not tolerate individuals who use intimidation and violence to stifle freedom of speech and legitimate political expression."

He said the State Department would work with police and legal authorities as the cases progress and decide on additional steps when that process is complete. Department spokeswoman Heather Nauert declined to say what actions might be taken, but the U.S. could seek the extradition of the Turkish suspects or bar them from entering the United States.

Tillerson's comment came shortly after District of Columbia Police Chief Peter Newsham and Mayor Muriel Bowser announced that arrest warrants had been issued for nine Turkish security guards, three Turkish police officers and two Canadians. Newsham urged those being sought and some still unidentified to surrender, speaking a day after two other people were arrested in the case.

The melee has become a major irritant in U.S.-Turkish ties and the charges appeared to escalate the situation Thursday.

Speaking at a dinner to break the Ramadan fast in Ankara, Erdogan asked, "What kind of a law is this?" Referring to his security detail, he said, "If they are not going to protect me, why would I bring them with me to America?"

Erdogan said the protesters were members of an outlawed Kurdish militant group and the U.S. police failed to act. He vowed to fight the decision on legal and political grounds.

Relations were severely strained even before the melee, which came as Erdogan arrived May 16 at the Turkish ambassador's residence after a White House meeting with President Donald Trump. Newsham said video showed security guards and some Erdogan supporters attacking a small group of protesters. Nine people were hurt.

"We all saw the violence that was perpetrated against the protesters," Newsham said. "We're not going to tolerate this."

He said many were being sought on assault charges, and other counts.

Erdogan's security detail returned with him to Turkey after his visit, so it was unclear if any would face any immediate U.S. legal repercussions. However, they could end up being threatened with arrest if they return to the U.S. If any are still in the country, they could be expelled if Turkey refuses to waive diplomatic immunity.

"They should bring themselves here to the United States to answer these charges," Newsham said.

Upon learning of the charges, Turkey's Foreign Ministry summoned John Boss, the U.S. ambassador to Turkey, to issue a protest.

The ministry said in a statement that the decision to charge the agents was "wrong, biased and lacks legal basis" and that the melee was actually the fault of U.S. law enforcement that failed to take necessary security steps. It also accused U.S. authorities of roughing up Erdogan's security detail.

"It has been emphasized that the decision, which clearly was not taken as a result of an impartial and independent investigation, is unacceptable," the ministry said.

Newsham recounted how video near the residence showed some people attacking protesters with their fists and feet. Men in dark suits and others were recorded repeatedly kicking one woman as she lay curled on a sidewalk. A man with a bullhorn was repeatedly kicked in the face. After officers struggled to protect the protesters and ordered the men in suits to retreat, several of the men dodged the officers and ran into a park to continue the attacks.

Bowser said the nation's capital is a frequent protest venue but police insist those be peaceful. "We make sure they are safe, but we also make sure they follow our laws," she said. "And certainly anyone travelling to the United States will be held to that standard."

Rep. Ed Royce of California, Republican chairman of the House Foreign Affairs Committee, said Thursday he was encouraged by the police action.

"The violent attacks by Turkish security forces on peaceful protesters in Washington were completely and totally unjustified," Royce said. "Now, the State Department should double down on efforts to help bring these individuals to justice."

Police displayed photos at the news conference of those sought, urging the public to help find some still unidentified.

Turkey has claimed the demonstrators were associated with the PKK, which has waged a three-decade-long insurgency against Turkey and is considered a terrorist group by the United States. Newsham said Thursday there was no indication that the protesters were part of a terrorist group.

"In Washington, D.C., we do not care particularly what your views are, what you support or what you do not support," Newsham said. "Our goal as a government, as a police department, is making sure you can do it safely."

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Associated Press writers Zeynep Bilginsoy in Istanbul and Josh Lederman in Washington contributed to this report.