In September 1999, a series of bombings struck apartment buildings in the Russian cities of Buynaksk, Moscow, and Volgodonsk, killing more than 300 people and injuring over 1,000. The blasts occurred on 4 September (Buynaksk), 9 and 13 September (Moscow), and 16 September (Volgodonsk). Each device used powerful explosives timed to detonate at night to maximize casualties, destroying or heavily damaging multi-story residential buildings. A preceding smaller bombing occurred at Moscow's Manezhnaya Square shopping complex on 31 August 1999, injuring at least 29 people.
Chechen militants were officially blamed for the attacks, but Chechen leaders, including President Aslan Maskhadov and commander Shamil Basayev, denied responsibility. An anonymous caller claiming to represent a "Liberation Army of Dagestan" claimed responsibility in calls to news agencies, but Russian officials expressed skepticism that such an organization existed, and a Dagestani official also denied its existence.
A significant controversy arose after a device resembling those used in the bombings was found and defused in an apartment building in Ryazan on 22 September 1999. Three Federal Security Service (FSB) agents were arrested by local police in connection with placing the device. The following day, FSB director Nikolai Patrushev announced that the Ryazan incident had been an anti-terror training exercise and that the sacks found in the basement contained only sugar, and the arrested agents were released.
Official investigations into the Buynaksk bombing concluded in 2001, resulting in convictions of several people. Investigations into the Moscow and Volgodonsk bombings concluded in 2002, with court rulings announced in 2004 finding that the attacks were organized by Achemez Gochiyaev, who remains a fugitive, and ordered by Islamist commanders Ibn al-Khattab and Abu Omar al-Saif, both of whom were later killed. Several other suspects were killed, and several were convicted on terrorism-related charges by Russian courts, including life sentences for some defendants.
Attempts to conduct an independent investigation faced obstruction. State Duma motions for a parliamentary investigation were rejected in March 2000. An independent commission chaired by Duma deputy Sergei Kovalev was unable to obtain government cooperation. Two members of that commission, Sergei Yushenkov and Yuri Shchekochikhin, later died in what have been described as apparent assassinations. The commission's investigator, Mikhail Trepashkin, was arrested and served four years in prison on a charge of revealing state secrets; Amnesty International stated there were serious grounds to believe the charges were politically motivated to stop his investigative work on the bombings.
A number of historians, journalists, and former security officials — including former FSB officer Alexander Litvinenko, who was later assassinated in London in 2006 — have alleged that the bombings were a false-flag operation carried out by Russian state security services to build public support for renewed war in Chechnya and boost the political standing of Vladimir Putin ahead of the 2000 presidential election. These allegations have not been conclusively proven, and the guilt of the Chechen militants officially blamed for the bombings has likewise never been conclusively established.