MOSCOW, March 30 (UPI) -- Moscow observed a day of mourning Tuesday for 39 people killed in two suicide-bomb blasts in the city's subway system.
Two female bombers detonated their explosives at the Lubyanka and Park Kultury subway stations during the morning rush hour Monday.
The 39th victim was a woman who had been critically injured in one of the blasts, Andrei Seltsovsky, chief of the Moscow Health Department, said in a report from the Russian news agency RIA Novosti.
Officials said at least 84 people sought medical attention after the explosions.
No one had claimed responsibility for the bombings, but Alexander Bortnikov, director of the Federal Security Service, said preliminary evidence indicated they were committed by "terrorist groups linked to the North Caucasus region," The Washington Post reported.
Leaders in the upper house of the Russian parliament said they will propose a bill that would seek the death penalty for organizers of terrorist attacks resulting in multiple deaths, RIA Novosti said.
Russian President Dmitry Medvedev laid flowers at the Lubyanka metro station and vowed the organizers of the attack would be punished, ITAR-Tass reported.
"These are animals. Irrespective of their motives, what they do is a crime by any law and any moral standards," Medvedev said. "I have no doubt that we will find and destroy them all."
The terrorist attacks counter Prime Minister Vladimir Putin's claim that a separatist insurgency has been contained, the Post said.
In recent weeks, it was reported that Russian security forces killed several leaders of the Islamic rebel movement seeking to establish a fundamentalist state in the North Caucasus region.
Sergei Markedonov, a specialist on the Caucasus at the Institute for Political and Military Analysis, told the Post the bombings may prompt a more serious debate on how to deal with the rebellion.
"Putin gained great popularity by demonstrating his readiness to crush terrorists," Markedonov said, "but I think after 10 years of brutal rhetoric and actions, it's time for a new understanding."