Up to a dozen militants have staged a daring attack on the capital of a Southern Russian republic popular with downhill skiers and budget tourists, news reports said on Saturday.
The overnight attack on Kabardino-Balkaria came a week after three Moscow tourists were gunned down in the area while travelling to the Elbrus mountain resort, which is one of Russia's most popular winter tourist destinations.
No one was reported killed in Friday night's strike on the republic's capital Nalchik, which witnessed grenades tossed at a local Federal Security Service (FSB) building and police posts come under repeated machine gun fire.
But the incident prompted a late night telephone conversation between President Dmitry Medvedev and FSB chief Alexander Bortnikov, the Kremlin said.
Highlighting the Kremlin's concern over the latest incident, news reports said that Medvedev's North Caucasus envoy Alexander Khloponin had taken personal charge of the investigation.
The Nalchik attack culminates a restless month in a region that until now has been largely able to avoid the deadly violence raging in nearby mostly Muslim republics such as Ingushetia and Dagestan.
Kabardino-Balkaria has been a popular destination with both skiers and mountain climbers, with its budget boosted by tourism revenues that continued to climb despite violence wrecking other parts of the Caucasus range.
But its ski slopes went empty on February 18 after two masked attackers stopped a minibus carrying six people on Friday evening and opened fire, killing three passengers instantly and wounding others.
A few hours later, an explosion targeted a ski lift in one of the Elbrus mountain resort areas. No one was reported hurt in that incident.
A message on Islamist website Islamdin.Com linked to the militant group Caucasus Emirate said the tourists were killed for entering "the war zone".
Military officials initially claimed killing three militants responsible for attacking the tourists.
But subsequent reports said the suspected Islamists had escaped into the region's mountains, which Russian forces have been pelting with artillery and aerial fire for much of the week.