North Caucasus: Guide to a volatile region

The North Caucasus region is the part of Russia that slopes up towards the main ridge of the Caucasus mountains, often considered the border between Europe and Asia.

It is home to dozens of nationalities and languages, many of which have troubled relationships with their neighbours or with central governments in Moscow or Tbilisi.

Status: Republic within Russian Federation

Population: 1.1m (figure is disputed)

Capital: Grozny

Languages: Chechen, Russian

Major religions: Islam

In April 2009 Russia said it had ended its decade-long "counter-terrorism operation" against separatist rebels in Chechnya. Yet sporadic attacks by Chechen militants have continued.

Chechnya declared independence from Russia in 1991, when the Soviet Union was collapsing.

Three years later the Kremlin sent in troops to restore its authority, sparking the first Chechen war. It ended in humiliating defeat for Russian forces in 1996.

In 1999, Russian troops poured back in. The war with rebel commanders, who had governed Chechnya since elections in 1997, resumed.

Militants from Chechnya and neighbouring republics have carried out major attacks outside Chechnya. The most notorious were: the deadly 2004 siege at a school in Beslan, North Ossetia; the mid-air destruction of two Russian airliners; the bombings at two Moscow metro stations; and the mass hostage-taking at a Moscow theatre in October 2002.

Chechen warlord Shamil Basayev was suspected of organising many of these operations. He died in an explosion in neighbouring Ingushetia in July 2006.

In recent years another Chechen separatist, Doku Umarov, has been seen as the leader of the Islamist insurgency across the northern Caucasus. He was linked to the attacks on the Moscow metro and on a luxury Moscow-St Petersburg express train, in which dozens died.

Backed by the Kremlin, Chechen President Ramzan Kadyrov has cracked down hard on the militants, leading to a reduction in the number of attacks on Chechen soil.

However, in October last year, six people died when militants stormed the parliament building in Grozny.

Mr Kadyrov has also overseen a big rebuilding programme in the capital, Grozny, which was devastated during the war.

But he and his militia have been accused of severe human rights abuses including kidnappings, torture and murder.

Some of his most prominent critics have been shot dead, including the investigative journalist Anna Politkovskaya and human rights activist Natalia Estemirova.

He denies any involvement in their murders.

Status: Republic within Russian Federation

Population: 300,000

Capital: Magas

Languages: Ingush, Russian

Major religions: Islam

Chechnya's violence has spread to Ingushetia in recent years, killing hundreds of people. As the Chechen crackdown on insurgents has taken hold, the number of attacks in Ingushetia has escalated.

Russian President Dmitry Medvedev has singled out growing violence in the North Caucasus as one of the most pressing problems Russia faces, describing the rise of separatists as "a cancerous tumour".

In 2004, hundreds of gunmen armed with grenades and rockets launched attacks in which 90 people died. And, as the insurgency grew, in June 2009, Ingush President Yunus-Bek Yevkurov was severely wounded and two of his bodyguards were killed when a suicide bomber attacked his motorcade.

A leading Islamist rebel in Ingushetia - Alexander Tikhomirov, also known as Said Buryatsky - was killed in March 2010. He is believed to have been linked to the attack on Mr Yevkurov, as well as a suicide bomb attack at police headquarters in the republic's capital, Nazran, in August 2009.

Like Chechen separatist Doku Umarov, he was named in connection with the November 2009 bomb attack on the Nevksy Express between Moscow and St Petersburg which left 29 dead.

In 1936, under Soviet rule, Ingushetia was joined to Chechnya.

The Ingush and Chechen peoples have close historical, cultural and linguistic ties and both were deported to Central Asia in 1944 by Stalin, who accused them of collaborating with the Nazis. Most of them returned in the 1950s.

At the time, Soviet authorities redrew the boundaries, giving some Ingush land to North Ossetia.

That sowed the seeds for a bitter conflict half a century later as, in 1992, Ingush forces moved into the disputed Prigorodny district, sparking a bloody conflict. Moscow sent troops to establish order and the Ingush population was expelled from the disputed areas.

Status: Republic within Russian Federation

Population: 709,900

Capital: Vladikavkaz

Languages: Ossetian, Russian

Major religions: Christianity

Historically, the North Ossetians, who speak an Iranian language, have had closer relations with Moscow than any other republic in the region.

North Ossetia is the most industrialised and urbanised republic in the North Caucasus and has escaped much of the violence that has beset its neighbours in recent years.

But a bloody conflict broke out with Ingushetia in 1992, prompting tens of thousands of ethnic Ingush to flee North Ossetia.

In 2004, Ingush fighters were alleged to have been part of an armed group behind one of the highest profile militant attacks ever to take place in Russia.

More than 1,000 people were taken hostage at a school in the North Ossetian town of Beslan. When the siege was brought to a violent end at least 330 people were killed, of whom more than half were children.

And there has been a series of suicide attacks. Fifty people died in August 2003 when a lorry blew up a military hospital in Mozdok. In September 2010, a suicide bomber attacked a market in the capital, Vladikavkaz.

Status: Republic within Russian Federation

Population: 2,584,200

Capital: Makhachkala

Languages: Dagestani group of languages, Russian

Major religions: Islam

Violence in Dagestan has escalated following the crackdown on militants in neighbouring Chechnya.

While Chechnya has appeared more peaceful, the republics of Dagestan and Ingushetia have seen a violent Islamist insurgency spread.

Dozens of people have been killed in militant attacks and gun battles between security forces and militants. The region has suffered numerous attacks on its infrastructure. In 2009, the region's interior minister was shot dead and in March 2010 two suicide bombers from Dagestan carried out the attacks on the Moscow metro.

Dagestan is the largest and most ethnically and linguistically diverse of all Russia's North Caucasian republics. It is also a conduit for oil exports from the Caspian Sea.

It is sometimes known as the Mountain of Languages, or Mountain of Nationalities - with some national groups occupying no more than one or two villages.

Dagestan kept out of the first Chechen war, though it was used by the Chechen rebels as a supply corridor.

In 1999, home-grown Muslim radicals were joined by guerrillas from Chechnya in an attempt to establish an Islamic state that was quickly stamped out by the Russian army.

Since then, Dagestan has been the scene of a number of bloody attacks - including one at a Victory Day parade in 2002 - and hundreds of kidnappings.

Status: Republic within Russian Federation

Population: 900,500

Capital: Nalchik

Languages: Kabardian, Russian

Major religions: Islam, Christianity

Two ethnic territories form Kabardino-Balkaria: one predominantly of Kabardin (who speak a Caucasian language) and the other predominantly Balkar (who speak a Turkic language). There is also a significant Russian population.

In 1944, Stalin accused the Balkars of collaborating with Nazi Germany and deported the entire population, removing their name from the republic's title. They were allowed to return only in 1957.

Friction between the two communities is rarely far from the surface.

In 1992, the Balkars - who account for about 8% of the population - voted for secession. Their 1996 proclamation of a new republic received little support in Kabardino-Balkaria itself, but was generally backed in Chechnya.

In October 2005 Chechen rebel leader Shamil Basayev orchestrated a major attack on Nalchik, the capital of Kabardino-Balkaria, in which dozens of rebels and members of the security forces died.

There have been sporadic clashes between security forces and small groups of militants in Kabardino-Balkaria since then.

Status: Breakaway region within Georgia

Population: 70,000 (approx)

Capital: Tskhinvali

Languages: Ossetian, Georgian, Russian

Major religions: Christianity

South Ossetia was one of the first flashpoints of ethnic conflict in the disintegrating Soviet Union when, in 1990, calls for unification with their ethnic kin in North Ossetia led to conflict with Georgia's new nationalist government.

Up to 1,000 people died in two years of fighting. After that South Ossetia remained under rebel control, with Russian forces acting as peacekeepers.

Simmering tensions flared up into all-out war between Georgia and Russia in South Ossetia in August 2008.

Georgia launched an assault on the South Ossetian capital Tskhinvali to flush out separatist rebels, following frequent exchanges of fire.

Russia responded by pouring thousands of troops into South Ossetia and launching bombing raids on Georgian targets.

Russian forces pushed further south, occupying a swathe of Georgian territory, before pulling back to South Ossetia. At the same time, Russia ousted Georgian troops from Abkhazia, another breakaway territory. Thousands of ethnic Georgians sought refuge in the rest of Georgia.

Russia has recognised both breakaway regions as independent states - a move widely condemned internationally - and vowed to defend their independence if necessary.

Status: Breakaway region within Georgia

Population: 536,000 before 1992, 250,000 after 1993

Capital: Sukhumi

Languages: Russian, Abkhaz

Major religions: None

Though geographically in the South Caucasus, Abkhazia's strongest kinship links are with North Caucasians.

Abkhaz separatists drove Georgian government troops out of the territory in 1993, a year after Tbilisi had intervened to halt Abkhaz moves towards increased autonomy. More than 200,000 ethnic Georgians fled Abkhazia.

A truce was upheld by Russian peacekeepers. Moscow continued to back the separatists.

The brief Georgia-Russia war of August 2008 consolidated Russia's grip on Abkhazia.

Fighting in the territory was less intense than in South Ossetia, but an offensive by Russian and Abkhaz separatist forces pushed Georgian troops out of the Kodori Gorge. That had been Georgia's only toehold in Abkhazia since the 1993 conflict.

Like South Ossetia, Moscow recognised Abkhazia as an independent state and correspondents say the region is receiving far more Russian investment than it did before.