MOSCOW -- Russian President Vladimir Putin on Saturday called a terrorist attack here bloody and barbaric, vowing retribution for the perpetrators, organizers and financiers.

Putin made the remarks during a televised address to the nation after a deadly shooting Friday evening at the Crocus City Hall in northwest Moscow claimed the lives of at least 133 people.

Putin said all four perpetrators of the terrorist attack were arrested, adding that all perpetrators, organizers and financiers of this crime would be punished.

"Whoever they are, whoever guides them. I repeat, we will identify and punish everyone who stands behind the terrorists, who prepared this atrocity. This is a strike against Russia, against our people," Putin said.

The Russian president added the terrorist attack was "carefully, cynically planned," and "a prepared mass murder of civilians."

He also said that the perpetrators tried to hide and moved towards Ukraine, and according to preliminary information, a "window" was prepared for them from the Ukrainian side to cross the border.

Earlier, advisor to the head of the Ukrainian Presidential Office Mikhail Podolyak and the Ukrainian Foreign Ministry both rejected the notion of Ukraine's involvement in the attack.

Putin added that the main thing now is to prevent those who were behind the terrorist attack from committing new crimes.

He noted that the Federal Security Service and other law enforcement agencies are working to identify the entire "terrorist support base."

Putin also declared March 24 a day of national mourning in Russia for those killed in the terrorist attack.