He said deployments from former Soviet countries showed that the alliance would not allow governments in the region to be overthrown.
"The measures taken by the CSTO made it clear that we would not let anyone destabilize the situation at our home and implement so-called color revolution scenarios," Putin said, referring to several revolutions in post-Soviet countries over the past few decades.
Putin said he wished to emphasize that the troops had been sent to Kazakhstan only for a "limited time." In addition to Russia and Kazakhstan, Armenia, Belarus, Kyrgyzstan and Tajikistan are also members of the alliance.
Demonstrations in Kazakhstan began just over a week ago in protest at a fuel price rise began. They developed into a wider protest against Tokayev's government and the influence of the former president, 81-year-old Nursultan Nazarbayev.
"The threat to Kazakhstan's statehood arose not because of spontaneous protests and rallies concerning fuel prices. It is because destructive internal and external forces took advantage of the situation," Putin said.
UN concerned over Kazakh troops donning blue helmets
The United Nations said it was deeply concerned after photographs emerged of Kazakh soldiers wearing UN uniforms during last week's unrest.
"We have conveyed our concern to the Permanent Mission of Kazakhstan about this," a UN spokesperson told news agency dpa.
Kazakh soldiers donned blue helmets bearing the UN insignia — gear that is usually worn by troops taking part in UN peacekeeping missions.
Soldiers from UN states are barred from wearing the helmets unless taking part in a peacekeeping mission, the UN spokesperson said.
What the Kazakh president said
President Kassym-Jomart Tokayev said the country had weathered an attempted coup d'etat coordinated by what he called "a single center."
Speaking to an online meeting of the Russian-led CSTO military alliance by video link, Tokayev said the hunt for "terrorists" was ongoing, but that order had been restored.
"Under the guise of spontaneous protests, a wave of unrest broke out... It became clear that the main goal was to undermine the constitutional order and to seize power. We are talking about an attempted coup d'etat," he said.
Tokayev said the country's largest city Almaty — along with 9 other regional centers — had been temporarily held by "bandits."
"The main blow was directed against (the city of) Almaty. The fall of this city would have paved the way for a takeover of the densely populated south and then the whole country," he said. "Then they planned to seize the capital."
The capital, Nursultan, lies in the north of the country, and is named after Nursultan Nazarbayev, who picked Tokayev as his successor.
Although soldiers were reported to have fired on demonstrators in Almaty last week, Tokayev said his security forces would "never fire" on peaceful protesters.
"Armed militants who were waiting in the wings joined the protests. The main goal was obvious: the undermining of the constitutional order, the destruction of government institutions and the seizure of power. It was an attempted coup d'etat," the president told delegates by videolink.