The media building burns as militants attack in central Grozny on December 4, 2014.ELENA FITKULINA/AFP / Getty Images
Russia's National Anti-Terrorist Committee says 10 police officers were killed and 28 wounded in gun battles with militants in the capital of Chechnya.
The leader of the Russian republic announced that at least nine of the militants were killed before the fighting ended.
The gun battles left a 10-story building and a school in ruins in the centre of the Chechen capital, Grozny.
The fighting early Thursday punctured the patina of stability ensured by years of heavy-handed rule by the Kremlin-appointed leader.
The violence erupted hours before Russian President Vladimir Putin gave his annual state of the nation address.
Although unrest is common across the North Caucasus, forceful security measures adopted by Chechen leader Ramzan Kadyrov have spared Grozny significant violence for several years. In October, however, a suicide bomber blew himself up outside a concert hall in Grozny, killing five policemen and wounding 12 others as the city celebrated Kadyrov's birthday.
The relative calm has allowed Putin to claim success in subduing an Islamic insurgency in Chechnya after years of war.
Kadyrov, who flew to Moscow on Thursday morning, was among the Russian federal and regional officials listening to Putin's address in a Kremlin hall.
The Kavkaz Center website, a mouthpiece for Islamic militant groups operating in Russia's North Caucasus, carried a link to a video message by an individual claiming responsibility for the attacks. The man in the video claimed to be operating under orders from Chechen Islamist leader Aslan Byutukayev, known to his followers as Emir Khamzat. The video could not immediately be verified.
A few years after the collapse of the Soviet Union, Chechnya was plunged into a full-scale war when separatist rebels pursued independence for the republic. The violence was largely confined to that small republic, but rebels ventured into other parts of Russia.
A fragile peace settlement was reached with Moscow until 1999, when an insurgency movement increasingly inspired by radical Islamist ideas reignited the conflict. A military crackdown succeeded by years of aggressive rule by Kadyrov has quietened the region, pushing unrest to neighbouring provinces.
Kadyrov has been widely denounced for human rights abuses, including allegations of killing opponents. He has also imposed some Islamic restrictions on the region, including mandatory public headscarves for women.