Russia's President Vladimir Putin has visited the city of Volgograd, the site this week's twin suicide bombings that left 34 people dead.
Mr. Putin laid flowers at the scene of one of the bombings and visited with survivors at a hospital in the city Wednesday.
In comments before a meeting with officials of the Interior Ministry and Federal Security Bureau, Mr. Putin said there was no justification for the attack.
"The abomination of this crime, that was - or crimes - that were committed here in Volgograd don't need any additional commentary. No matter what motivated the criminals' actions, there is no justification for committing crimes against civilians, especially against women and children."
Sunday's bombing at a security entrance of Volgograd's main train station killed 18 people and Monday's blast on a trolley bus left 16 dead.
Volgograd has been under heavy security since the attacks with authorities deploying more than 5,000 security personnel in and around the city.
No one has claimed responsibility for planting the bombs, which authorities say were similar in construction and likely linked.
Mr. Putin on Tuesday vowed to fight terrorists until their total destruction, saying Russia has always been united and consolidated at its most trying times.
The attacks came just weeks before the Winter Olympics open in Sochi, about 650 kilometers southwest of Volgograd. Islamist militants had threatened to attack civilians and disrupt the Winter Games.
The International Olympic Committee expressed its condolences over the bombings, but says it is confident of Russia's ability to provide security.
Russia has introduced some of the most stringent security at any international sporting event, including a limited access security cordon around the entire city of Sochi and requiring spectators to have accreditation documents that include passport details and contact information.