Civilians are feared to be among 60 people killed in clashes between police
and gunmen in Russia's volatile North Caucasus, say Russian media reports.
President Vladimir Putin has ordered Nalchik city in Kabardino-Balkaria province
to be sealed off and for forces to shoot any armed resisters.
Officials say armoured vehicles and troops have been deployed and the situation is returning to normal.
Militants from nearby Chechnya are believed to be behind the attacks.
A pro-rebel website said it had received information from rebel sources that a unit of Chechen armed forces had entered Nalchik, the capital of Kabardino-Balkaria.
'All-out attack'
A school and the city's airport, as well as government buildings, were caught
up in the running gun-battles.
Reporters in Moscow say this appears to have been an all-out attack on Nalchik's
law enforcement and security services.
Fighting broke out in the Belaya Rechka area early on Thursday and spread
to several parts of the city.
A local Interior Ministry source told Itar-Tass that rebels launched a "carefully planned" simultaneous attack on police stations, Russia's federal security forces, military and drugs-control offices as well as the airport.
One unidentified security official has told Russian news agency Ria that the reason for the attack was the arrest on Wednesday of at least one radical extremist.
Correspondents say violence in Kabardino-Balkaria has been steadily increasing.
Political changes and a harsh crackdown on alleged Islamic militants appear
to have pushed the region to the verge of instability, the BBC's regional
analyst Steven Eke says.
'Eliminated'
Russian Deputy Interior Minister Alexander Chekalin said Mr Putin ordered
the city to be completely sealed off to ensure not a single fighter could
escape.
"Those who resist will be eliminated," he said.
He was also quoted as saying he knew of no civilians killed in the fighting.
A witness told the BBC she had seen the bodies of gunmen, soldiers and civilians in the streets. Earlier, regional President Arsen Kanokov said 12 civilians had died.
A third of the 150 rebels who took part in attacks had been killed, he told Itar-Tass news agency.
Five police officers had also died, Mr Putin's special envoy to the area, Dmitry Kozak, told Russian television.
He also said the gunmen had stormed one police station and taken hostages.
But officials quoted by Itar-Tass said they were later freed, although there were no details.
Mr Kozak said that overall the city was under control.
Website claim
The pro-rebel Kavkaz Center website said that a detachment of the Chechen-linked
Kabardino-Balkaria jamaat, called Yarmuk, had entered Nalchik.
The use of the word jamaat indicates that it is made up of radical Islamic
fighters.
The attacks are the latest in a series of disturbances that have been destabilising Russia's North Caucasus region for more than a year.
Correspondents say Nalchik is about 100 km (60 miles) north-west of Beslan, where Chechen rebels took hundreds of hostages at a school in 2004, in an attack claimed by warlord Shamil Basayev.
Our analyst says that after last year's Beslan massacre the government promised
more money and support for the impoverished North Caucasus - but nothing has
changed.
© Gigaware™ Ltd 2005