Officials say the organized attack is believed to have been carried out by Islamist extremists. Such violent attacks are rare in Kazakhstan's closed society, but there has been an upturn in the past five years.
At least six people, including three militants, were killed during an attack on a military facility in Kazakhstan on Sunday.
Nine soldiers were also injured. Security forces responded with a counterterrorism operation that led to three attackers being killed and one being captured in the city of Aktobe, according to Almas Sadubayev, an interior ministry spokesman.
"Several criminals have been blocked in, and some were able to flee," he said, without being more precise.
He said the suspected attackers were "followers of radical, nontraditional religious movements," a phrase often used by Kazakh officials to describe Islamist militants.
The militants killed a clerk at a firearms store, a military officer and a serviceman at a National Guard facility, according to Sadubayev. Nine military personnel were also wounded.
Police hunt for militants
Police have temporarily shut down shopping malls and entertainment venues in the city as well as public transportation.
Aktobe is an industrial city of about 400,000, located 60 miles (100 kilometers) from the Russian border. It was the site of Kazakhstan's first suicide bombing in 2011, when a local man set off an explosive device inside the headquarters of the state security service.
Officials in the predominantly Muslim nation frequently announce detentions and trials of Islamist militants. Most of them are people who had traveled or planned to travel to places such as Syria and Iraq.
Violent clashes inside Kazakhstan are rare.
bik/rc (Reuters, AFP, AP, dpa)