A Moscow court has sentenced four men to jail terms for their roles in a suicide bombing on a major Russian airport that killed 37 people in January 2011.
Islam and Ilez Yandiyev, Akhmed Yevloyev and Bashir Khamkhoyev were jailed on Monday for offences including commissioning an act of terror, murder and attempted murder over the attack on Domodedovo International Airport in Moscow.
Khamkoyev and the Yandiyev brothers were sentenced to life terms in a penal colony while Yevloyev will spend 10 years in jail as he was a minor at the time of the attack.
Authorities say the suicide bombing was carried out by Magomed Yevloyev, Akhmed's brother, on the orders of the leader of the "Caucasus Emirate" movement, Doku Umarov.
The men were accused of sheltering the bomber in the city of Nazran in Ingushetia, providing him with money and putting him on a bus to Moscow in preparation for the attack.
Investigators said that his attack was plotted at a camp run by a Caucasus Emirate in Ingushetia.
The group seeks to establish an Islamic republic in Russia's volatile North Caucasus area and has threatened to disrupt next year's Winter Olympic Games in the Black Sea resort of Sochi in February.
The Russian president, Vladimir Putin, sent troops to Chechnya to halt a separatist rebellion in 1999, when he was prime minister, but Russia still faces almost daily violence in the North Caucasus in his third term as president.