At least three people are dead, including two law enforcement officers, after a shoot-out in the capital of Russia's North Caucasus region of Chechnya.
Unknown assailants initiated the assault on police on December 28, local media quoted sources as saying.
Interfax and TASS said the attackers opened fire on police, while other media said they attacked the officers with knives as they tried to disarm the law enforcement officials.
Interfax reported that two attackers were killed when police fired on them, while TASS said one was killed.
A search operation is now under way in the area as police investigate the attack.
Chechnya and Russia's other mostly Muslim-populated North Caucasus regions are the site of frequent fighting between government forces and militants whose insurgency stems from two post-Soviet separatist wars in Chechnya.
The volatile North Caucasus in recent years has also been at the epicenter of organized criminal gang violence linked to business turf wars, political disputes, clan rivalries, and the spread of militant Islam.