All night and into the early hours on Thursday, young men roamed the streets of Kazakhstan’s largest city, Almaty, flanked by flames and buttressed by barricades. As stun grenades exploded and tear gas wafted in the air, demonstrators set fire to trucks, police cars and other vehicles, their smoldering hulks littering the streets.
As the first foreign soldiers from countries allied with Russia landed in the Central Asian nation, they found a country that had, for the moment, been plunged into anarchy.
Some protesters came with firearms and started looting shops and malls, according to video footage posted from the scene. They set government buildings on fire, including the City Hall and the former office of the country’s president. They also captured the airport.
The scale of the violence, which was evident in videos, postings on social media and official government statements, was still coming into focus on Thursday morning as new and unconfirmed reports of sporadic clashes circulated on social media.
With intermittent internet access and few independent witnesses, information coming out of the country was hard to verify.
Galym Ageleulov, who has witnessed the events of the past few days, said he believed that a protest movement that was calling for peaceful change had been co-opted by throngs of criminals. Overnight, the streets were filled with mostly young men, many posing on social media with riot shields and helmets captured from the police. They were highly organized and managed by gang leaders, he said.
“The police have disappeared from the city,” said Mr. Ageleulov, director of the human rights center Liberty in Almaty. “These gang members marched through the city looting stores and setting cars ablaze as they moved; they stormed the City Hall,” he said in a phone interview.
“It was a horrible scene,” he said.
By the morning, Almaty had been transformed: Commercial banks were ordered closed with many Kazakhs rushing to A.T.M.s desperate to withdraw cash; stores were closed, causing many residents line up for bread, a scene unseen in the country for decades; at times, the internet has been shut down, disrupting basic infrastructure work.
Almaty’s City Hall, an imposing white building that once served as the Communist Party headquarters, was charred black from the flames that burned through the night. Members of the special forces roamed the surrounding streets firing live ammunition trying to quell the uprising.
The revolt began on Sunday in western Kazakhstan as a protest against a surge in fuel prices. Even though the government said it would rescind the price increase, the protests widened, spreading across the country, with broader demands for increased political representation and improved social benefits.
The Kazakh president, Kassym-Jomart Tokayev, issued a statement late Wednesday night calling the protesters “a band of terrorists” who had been trained abroad. He declared Kazakhstan to be under attack and asked for intervention from Russia’s answer to NATO, the Collective Security Treaty Organization, to which his country belongs.
The group is effectively led by Russia and also includes former Soviet countries in the Kremlin sphere of influence: Armenia, Belarus, Kyrgyzstan and Tajikistan.
The protests have paralyzed a nation of 19 million. In addition to the bank closures and internet shutdowns, the telephone system has been shut off sporadically, schools have extended their winter break by a week and flights in and out of airports in the cities of Almaty, Aktau and Aktobe have been suspended.
The New York Times