"Russian special services and law enforcement agencies continue to investigate, to look into the details of this despicable crime. They are identifying people behind it, including those who commissioned the attack, sponsors and organizers," Putin told the 12th International Meeting of High Representatives for Security Issues in the Russian city of St. Petersburg via a video message.
None of those guilty of the attack shall escape just retribution, the president added.
"Criminals' methods are becoming more and more sophisticated and barbaric. This was once again demonstrated by the bloody terrorist attack that took place near Moscow on March 22," Putin also said.
The 12th International Meeting of High Representatives for Security Issues is being held under the auspices of the Russian Security Council from Tuesday to Thursday. Russian Security Council Secretary Nikolai Patrushev is representing Russia at the meeting.