Dozens of people died in protests sparked by rising fuel prices, but Blinken said the US believed that the Kazakh government could handle the protests on its own.
He told reporters it was not clear why the violence took place. The first of about 2,500 Russian-led troops had arrived in Kazakhstan.
Officials in Moscow have stressed that the deployment of its troops under the Collective Security Treaty Organization (CSTO), the Eurasian military alliance of the five former Soviet republics and Russia, is temporary.
President Kassym-Jomart Tokayev made a request for help after protesters stormed the mayor’s office in Kazakhstan’s largest city, Almaty, and stormed the city’s airport.
But speaking to reporters at a State Department briefing, Blinken warned that “one lesson from recent history is that once Russians are in your home, it is sometimes very difficult to get them to leave”.
“It seems to me that the Kazakh authorities and government definitely have the capacity to properly handle protests to do so in a way that respects the rights of protesters while maintaining law and order,” Blinken said.
“So it’s not clear why they feel they need outside help. So we’re trying to learn more about that.”
Several units of Russian paratroopers have arrived in the country, and on Friday assisted Kazakh troops in retaking the airport from protesters. Meanwhile, Kazakh forces have taken decisive action to regain control of Almaty.
On Thursday, local media published a video showing government forces shooting at protesters.
The Interior Ministry said 26 “armed criminals” and 18 security officers had died so far in the clashes and President Tokayev blamed what he called foreign “terrorists” for the unrest.