In a shocking development, Russian President Vladimir Putin has suggested that Ukraine may have been linked to the deadly attack on a concert hall in Moscow. The attack, which resulted in the death of at least 133 people, is just the latest in a series of bombings and sieges that have unsettled and outraged Russians during Putin's long tenure.

The attack took place at the Crocus City Hall and was claimed by an Islamic State faction based in Afghanistan. While the region had experienced relative calm in recent years, the scale and cruelty of this attack make it one of the most violent and shocking in Russian history.

This incident comes in the context of several major attacks that have occurred since Putin first became Russia's prime minister back in August 1999. In September of that year, four apartment buildings in Moscow and other cities were bombed over a two-week period, resulting in the tragic deaths of 307 people. Officials initially blamed militants from the separatist region of Chechnya for the bombings, but doubts about their involvement arose when sacks of explosives were found in an apartment building in Ryazan. This discovery led to the detention of three men who were identified as members of the Federal Security Service, which Putin had previously headed. The security service later claimed that it was conducting a drill and the sacks contained harmless material, but the incident served as a justification for Putin to launch a military campaign in Chechnya, marking the beginning of a full-scale war in the region.

Another significant attack occurred in October 2002 when around 40 Chechen militants stormed a Moscow theater during a performance, taking over 850 people hostage. Explosives were planted in the auditorium, and the hostage-takers demanded the withdrawal of Russian forces from Chechnya. Russian special forces chose not to storm the theater due to its difficult layout and the presence of explosives. Tragically, after days of negotiations, Russian forces pumped a sleeping gas into the ventilation system, killing the assailants but also resulting in the deaths of 132 hostages.

In 2004, a horrific event unfolded in the town of Beslan, near Chechnya, when Chechen warlord Shamil Basayev led an attack on a school on the first day of school. Over 1,100 hostages, mostly children, were held in the school's auditorium. Two days later, Russian forces stormed the building, resulting in the deaths of 334 civilians and 31 attackers.

Russia's subways have also been frequent targets for attacks. In 2004, a suicide bomber killed 41 people on a Moscow subway train. Then, in 2010, two separate suicide bombings on Moscow subway trains claimed the lives of approximately 40 people. Furthermore, in 2013, suicide bombers targeted a train station and a bus in Volgograd on consecutive days, resulting in the deaths of 34 people.

These series of attacks have deeply shaken the Russian population, and Putin's suggestion of a possible Ukrainian link in the recent concert hall attack will only add fuel to the already tense relations between the two countries. The investigation into the attack is still ongoing, and it remains to be seen what evidence will emerge to support or refute Putin's claims.