At least 17 people, including 11 "extremists", were killed during a series of attacks in oil-rich Kazakhstan, an increasingly authoritarian ex-Soviet nation that has largely avoided violence by religious zealots, officials said Monday.

Groups of gunmen attacked two arms shops to seize weapons and rammed a minibus through the doors of a national guard base in the northwestern Kazakh city of Aktobe on Sunday, Interior Ministry spokesman Almas Sadubayev said in televised remarks.

He said the attackers killed three civilians and three security officers and wounded scores more, but were repelled in a counterterrorism operation. Eleven assailants were killed and seven more captured.

Sadubayev said the attackers followed "radical, non-traditional religious movements", a euphemism used in Kazakhstan to refer to hardline Muslim fighters.

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However, one analyst expressed doubt over the official version, saying law enforcement agencies often imitate counterterrorism operations by accusing average criminals of siding with religious fighters.

"Kazakhstan is actively fighting the so-called religious extremism, but these cases are not covered by mass media and are not studied by human rights activists," a Central Asia analyst, Maria Yanovskaya, told Al Jazeera. "Sometimes they arrest a group [of people] for robbing a shop and accuse them of financing terrorism."

Unlike Russia and Kazakhstan's other ex-Soviet neighbours in Central Asia, the oil-rich nation of 18 million has rarely seen attacks instigated by religious hardliners.

But Aktobe, a city of 400,000 near the Russian border, was the site of the first suicide bombing in Kazakhstan's history in 2011.

Another assailant carried out an attack in 2011 in the southern city of Taraz.

The attacker followed a scenario similar to Sunday's violence in Aktobe - he seized weapons at a gun shop, killed several police officers, and attacked a local security service office, where he fired several grenades and then blew himself up.

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Dozens of Kazakh nationals have joined the Islamic State of Iraq and Levant (ISIL, also known as ISIS), officials say.

In January 2015, a child soldier who claimed to have come from Kazakhstan was seen executing two alleged Russian spies in a video released by ISIL.

In other videos and statements, ISIL members from Kazakhstan and other Central Asian states called Kazakh President Nursultan Nazarbayev a "kafir", or infidel, and vowed to turn the nation he has ruled since 1989 into an ISIL province.

Nazarbayev is widely praised for turning Kazakhstan into one of the most prosperous former Soviet states. But his rule has been growing increasingly heavy-handed, with political opponents jailed and marginalised. Some have even been murdered.

In recent weeks, Kazakhstan has been roiled by a series of massive protests against legislation that allows foreigners to buy land. Dozens of protesters, several businessmen and officials have been arrested during and after the protests and accused of planning a coup.

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The political problems of Kazakhstan are echoed throughout Central Asia, a strategic region that borders Russia, China and Afghanistan, where secular leaders often rule for decades and see the post-Soviet revival of Muslim traditions and the emergence of violent groups as the biggest threat to their own political future.

"The governments of Central Asian republics either hide the true scope of Islamist threat, or accuse peaceful Muslims of carrying out terrorist attacks or planning to topple their secular regimes," Moscow-based analyst Daniil Kislov told Al Jazeera.