Gunfire rang out and buildings were set ablaze in Grozny this morning as the Chechen capital witnessed a battle that left at least 10 policemen and nine militants dead.

More than six hours after fighting broke out, Chechen leader Ramzan Kadyrov said a multi-story building the militants had occupied in central Grozny had been destroyed by fire and six gunmen killed.

He later raised the total number of dead gunmen to nine after several more were found in a city school and an operation launched to 'liquidate' them. Several buildings in the city were left devastated by fire.

Scroll down for video

Blaze: A publishing house building is seen in flames in the centre of Grozny early this morning after gunmen launched an attack in the capital of the Russian republic of Chechnya

Inferno: Chechen leader Ramzan Kadyrov said the building in central Grozny had been occupied by the militants before it was destroyed by fire and six gunmen killed

Crackdown: In this photo released by the Anti-Terrorist Committee, armoured personnel carriers are parked in downtown Grozny as security forces respond to the attack on the city by militants

Military zone: Heavily armed personnel mill around their APCs as they battle to end the attack

Operation: Security personnel can be seen in cover as the multi-storey building burns with the gunmen inside

Security: A Chechen Interior Ministry servicemen stands guard at the site of the counter-terrorism operation

Unrest is common across the North Caucasus, which has been gripped by an Islamist insurgency going back to the collapse of the Soviet Union. But forceful measures have spared Grozny significant violence for several years.

Security officials and Mr Kadyrov said militants travelling in several cars killed three traffic police at a checkpoint in Grozny. This was disputed by Russian state news agency RIA-Novosti, which cited an unidentified law enforcement source as saying five police officers were killed.

An Associated Press reporter saw the building - a publishing house - in flames and heard the sound of heavy-calibre gunfire before dawn, several hours after the unrest erupted.

The AP reporter also saw the body of someone in civilian clothing in the street near the publishing house as fighting continued. It was not clear how and when the person had been killed.

The Moscow-based National Anti-Terrorist Committee, a federal agency, announced it had imposed a counter-terrorism regime on the centre of Grozny.

This officially allows heightened security measures to be enforced, and typically indicates the imminent use of heavy force to quash unrest.

Life News, a news outlet believed to have links to Russian security services, cited police as saying about 15 people had seized three cars late last night in the village of Shalazhi and drove to Grozny, some 30 miles away.

Aftermath: Smoke rises from the publishing house as the sun rises on a bleak morning in Grozny

Ongoing: Chechen leader Ramzan Kadyrov said several other gunmen had been found in a city school and an operation was underway to 'liquidate' them, according to Russian news agency Interfax

Daily life: Local women look at smoke rising from the publishing house

Mr Kadyrov said on his Instagram account, which he uses to issue public statements, that the traffic police officers were shot dead as they attempted to stop the cars carrying the gunmen.

In a message posted several hours later, Mr Kadyrov said that six militants were killed in the standoff at the publishing house.

'Not one bandit managed to get out. I directly ran the operation myself,' he wrote.

Mr Kadyrov posted a picture showing the lower half of an apparently dead gunman lying beside a rifle. It was not immediately clear if it showed one of the attackers.

Dmitry Trenin, chief of the Carnegie Moscow Center, wrote on Twitter 'the night attack in Grozny looks senseless, except as an attempt to embarrass (Russian president Vladimir) Putin hours before his annual address to parliament.'

Mr Putin, who is to give his state of the nation address on Thursday, already was under pressure to reassure Russians as fears grow over soaring inflation and a plummeting ruble.

A fresh outbreak of violence could further damage Mr Putin, who has been able to claim success in subduing Chechnya's Islamic insurgency after years of violence and two full-scale wars.

But militant jihadist group the Caucasus Emirate, which follows a hardline Salafist Muslim ideology, has continued to launch attacks despite Chechen separatists officially ending their armed resistance.

Probe begins: An Investigative Committee minivan is parked outside the burned publishing house

Gunfire: Shell casings lie on the floor close to the burned out building after the fierce battle this morning

More fire: A police car parked outside the burned out market pavilion in central Grozny

Clean up job: Firefighters and a salesman try to save goods at the burned market pavilion

More destruction: A man looks downcast as firefighters tamp down the blaze at the market pavilion

Upset: Two women greet each other outside the burned-out market pavilion as Grozny woke to devastation

Solidarity: The women put their arms around each other as they contemplate what they've lost in the violence

In Moscow: Chechen regional leader Ramzan Kadyrov, center, talks with the media after Russian President Vladimir Putin gave his annual state of the nation address in the Kremlin in Moscow earlier today

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.

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 Mr Kadyrov has quietened the region, pushing unrest to neighbouring provinces.

Mr 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.