(Reuters) - The two brothers suspected of carrying out the bombing of the Boston Marathon have been identified as Chechens. The motives for the attack are not clear.
Their home region in southern Russia has been the focus of two wars, in which Chechnya has sought to break away from Moscow, and a guerrilla conflict.
Here is an overview of major attacks on Russian soil since the beginning of the first Chechen war in 1994:
June 1995 - Chechen rebels seize hundreds of hostages in a hospital in the southern Russian town of Budennovsk. More than 100 people are killed during the rebel assault and a botched Russian commando raid.
January 1996 - Chechen fighters take hundreds hostage in a hospital at Kizlyar in Dagestan, a neighbor of Chechnya in southern Russia, then move them by bus to Pervomaiskoye on the Chechen border. After being pounded by Russian military, most rebels escape but hostages are killed.
June 2000 - Five suicide bomb attacks, carried out by Chechen rebels, on police stations and Russian army bases in Chechnya kill at least 54 people.
October 2002 - 129 hostages and 41 Chechen guerrillas are killed when Russian troops storm a Moscow theatre where rebels had taken 700 people captive three days earlier. Most of the hostages are killed by gas used to knock out the Chechens.
February 2004 - A suicide bombing kills at least 39 people and wounds more than 100 on an underground train in Moscow, in what police say is the work of Chechen separatists.
June 2004 - Rebels seize an interior ministry building in Ingushetia, near Chechnya, and attack other points in lightning raids. At least 92 people are killed including the acting regional interior minister, Abukar Kostoyev.
September 2004 - 331 hostages - half of them children - die in a chaotic storming of a school in Beslan, after it is seized by rebels demanding Chechen independence and an immediate end to the war.
November 2009 - A bomb blast derails the Moscow/St Petersburg Nevsky Express train with about 700 people on board. At least 26 people are killed and 100 injured. Chechen rebels claim responsibility.
March 2010 - At least two blasts strike Moscow metro stations during rush hour, killing 40 people.
January 2011 - At least 36 people including eight foreigners are killed and more than 130 injured in a suicide bombing at Moscow's Domodedovo airport, Russia's biggest. Islamist insurgent Doku Umarov later claimed responsibility for the last two attacks.
(Reporting by David Cutler, London Editorial Reference Unit; editing Ralph Boulton/Janet McBride)