Russian forces have killed 11 militants in Chechnya in the northern Caucasus.

The dead included the Russian Federation's two most-wanted Islamic insurgent leaders, the brothers Muslim and Khusein Gakayev, adding that a counter-terrorist operation has been under way in Chechnya's south since Wednesday, Chechen President Ramzan Kadyrov said.

Two years ago, Kadyrov announced a $330,900 reward for information about brothers' whereabouts after the pair allegedly launched an attack against Kadyrov's native village of Tsentoroi.

Despite the apparent victory, violence continues to roil the Russian Federation's Caucasian republics of Chechnya, Dagestan, Ingushetia and Kabardino-Balkaria, Radio Free Europe/Radio Liberty reported Thursday.

Violence erupted in Chechnya following the December 1991 implosion of the Soviet Union when the Chechen-Ingush ASSR was split into the Republic of Ingushetia and the Chechen Republic. Chechen leaders under President Dzhokar Dudyaev had earlier proclaimed the Chechen Republic of Ichkeria in November 1991, which sought independence.

The First Chechen War lasted 1994-96, when Russian President Boris Yeltsin sent Russian military forces attempted to regain control over Chechnya. Despite overwhelming manpower, weaponry and air support, Russian forces were unable to establish effective permanent control over the mountainous area due to many successful Chechen guerrilla raids, with the fighting centered on the Chechen capital Grozny, which was effectively leveled.

In 1995 the Budyonnovsk hospital hostage crisis in 1995 shocked the Russian public, as it indicated that Chechen guerrillas could operate far from the Caucasus, but the brutal nature of the siege alienated many Russians.

The stalemate in Grozny produced widespread demoralization of the Russian forces and in the aftermath of a successful counteroffensive on Grozny by Chechen resistance forces led by Aslan Maskhadov led Yeltsin to declare a cease-fire in 1996 and sign a peace treaty the following year.

In the aftermath of the First Chechen War, the country gained de facto independence as the Chechen Republic of Ichkeria. Russian federal control was restored during the brutal Second Chechen War, which erupted in August 1999, when the Islamic International Brigade under the leadership of Shamil Basayev, who had led the Budyonnovsk hospital raid, began an incursion into the neighboring Russian republic of Dagestan in an effort to create a unitary Chechen-Dagestan unitary Islamic state.

The month after the invasion began, a series of apartment bombings that killed 300 Russian civilians took place in several Russian cities, including Moscow, which were blamed on Chechen separatists.

The second Chechen war took another political turn when, in August 1999,Yeltsin appointed Vladimir Putin as prime minister. On Dec. 31, Yeltsin unexpectedly resigned as the Russian Federation's president and, according to the constitution, Putin became acting president. Putin went on a previously scheduled visit to Russian troops in Chechnya and determined to intensify the conflict.

After the recapture of Grozny in February 2000, the Ichkerian regime collapsed, but Chechen guerrillas were able to mount assaults outside the republic, most notoriously seizing the Nord-Ost theater in Moscow on Oct. 23, 2002.

The death toll after the Russian security forces recaptured the building from Chechen insurgents was roughly 50 insurgents killed by the Russian counter-terrorism forces, along with more than 100 hostages.

Russia succeeded in installing a pro-Moscow Chechen regime, and on March 8, 2005 killed former Chechen President Aslan Maskhadov. Basayev was killed by Russian security forces on July 10, 2006. In April 2009 Russia ended its counter-terrorism operation and pulled out the majority of its armed forces.

Since then Moscow has begun a rebuilding campaign under Kadyrov but intermittent violence continues.