Both the attackers were shot, Tass reports. One died instantly, while the other later succumbed to his injuries. Two officers involved in the incident were injured, one seriously.
Police were investigating various motives for the attack, including a personal disagreement or an attempt to steal weapons. However, the Amaq news agency, which is linked to the Islamic State, released a statement Thursday claiming that the two men were "fighters from the Islamic State."
The report cited a "source" as having provided the information.
Amaq often serves as a channel for the Islamic State, also known as ISIS and ISIL, to claim responsibility for attacks it directed or inspired. The Wednesday incident appears to have been the first attack claimed in Russia by the Islamic State, though local affiliates have asserted responsibility for some attacks in Dagestan, a Russian republic in the North Caucasus region.
Amaq also released a video that it said was recorded by the attackers. The video shows two young men speaking in broken, heavily accented Russian and pledging allegiance to Islamic State leader Abu Bakr al-Baghdadi. The two men say they are carrying out an operation in retaliation for the killings of their "brothers" in Syria and Iraq.
Russian authorities have not named the attackers, but an unnamed source told the Interfax news agency that the two men were natives of Chechnya, a mostly Muslim Russian republic that was the site of two brutal wars in the years after the Soviet Union collapsed. The two men had left Chechnya on Monday, the source told Interfax, telling relatives that they were looking for work. They were not previously known to authorities.
Russia is a major military backer of Syrian President Bashar al-Assad in the country's civil war, and it has often attacked the Islamic State and other rebel groups there with airstrikes. At the start of August, Reuters reported that the Islamic State had released a video calling on its supporters in Russia to carry out attacks. "Listen Putin, we will come to Russia and will kill you at your homes," a masked man said in the video, referring to Russian President Vladimir Putin.