President Vladimir Putin has called Russia's deadliest bombings in three years an "abomination" as he visited the sites of two suicide strikes that killed 34 in the run-up to the Sochi Winter Olympic Games.
"The abomination of the crime that was committed here in Volgograd needs no extra commentary," Putin said during an unannounced visit to the industrial city of one million on the Volga River.
"No matter how the criminals may justify their actions, there is no justification for crimes committed against civilians, especially against women and children," the Russian leader said in televised remarks on Wednesday.
A bombing at the main railway station of the southern city killed 18 people on Sunday while a second strike that hit a trolleybus on Monday claimed 16 lives.
The blasts are Russia's deadliest since a suicide raid on Moscow's Domodedovo airport that was claimed by Islamic insurgents from the North Caucasus killed 37 people in January 2011.
The latest violence has laid bare the unchecked threat posed by insurgents who have vowed to target civilians in a bid to undermine Putin's preparations ahead of the Games' opening ceremony on February 7.
Putin in his first comments on the attacks on Tuesday promised to "toughly and consistently continue to fight against terrorists until their total destruction".
Investigators have opened a criminal probe into a suspected act of terror as well as the illegal carrying of weapons.
The chief spokesman for the Investigative Committee - Russia's equivalent to the US FBI - said the signature of the two bombings suggest that they were plotted by the same group.
The identical makeup of the explosives "confirms the theory that the two attacks are linked. It is possible that they were prepared in the same place," Investigative Committee spokesman Vladimir Markin said.
