WATCH: White House press secretary Jen Psaki holds briefing amid Kazakhstan protests

The White House on Thursday said it was “closely monitoring” reports that the Collective Security Treaty Organization had dispatched its collective peacekeeping forces to Kazakhstan, amid violent clashes.

Watch Psaki’s remarks in the player above.

“We have questions about the nature of this request and whether it has, it was a legitimate invitation or not, ” White House press secretary Jen Psaki told reporters in Washington.

Security forces killed dozens of protesters and 12 police died during extraordinarily violent demonstrations in Kazakhstan that saw government buildings stormed and set ablaze, authorities said Thursday. One police officer was found beheaded in escalating unrest that poses a growing challenge to authoritarian rule in the Central Asian nation.

Tens of thousands of people, some reportedly carrying clubs and shields, have taken to the streets in recent days in the worst protests the country has seen since gaining independence from the Soviet Union three decades ago.

Although the demonstrations began over a near-doubling of prices for a type of vehicle fuel, their size and rapid spread suggest they reflect wider discontent in the country that has been under the rule of the same party since independence.

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President Kassym-Jomart Tokayev on Wednesday appealed to the Collective Security Treaty Organization, a Moscow-based alliance of six former Soviet countries, for assistance. Hours later, the CSTO’s council approved sending an unspecified number of peacekeepers, said Armenian Prime Minister Nikol Pashinyan, the council’s chairman.

“The world will, of course, be watching for any violation of human rights and actions that may lay the predicate for the seizure of Kazakh institutions,” Psaki said.

“And we call on the CSTO collective peacekeeping forces and law enforcement to uphold international human rights obligations in order to support a peaceful resolution.”

The operation is the first military action by the CSTO – an indication that Kazakhstan’s neighbors, particularly Russia, are concerned that the unrest could spread.

Russia and Kazakhstan share close relations and a 7600-kilometer (4700-mile) border, much of it along open steppes. Russia’s manned space-launch facility, the Baikonur Cosmodrome, is in Kazakhstan.

The size and duties of the force have not been specified. Russia has already begun sending forces, according to the CSTO, which also includes Kazakhstan, Armenia, Belarus, Kyrgyzstan and Tajikistan. But Kyrgyzstan’s presidential spokesman, Erbol Sutanbaev, said his country’s contingent must be approved by parliament and said that the troops would not take actions involving demonstrators.

It was not immediately clear if any of the Russian forces had arrived in Kazakhstan.

U.S. Secretary of State Antony Blinken spoke by telephone with his Kazakh counterpart, Mukhtar Tileuberdi, and “reiterated the United States’ full support for Kazakhstan’s constitutional institutions and media freedom and advocated for a peaceful, rights-respecting resolution to the crisis,” said State Department spokesman Ned Price.