Russian Prime Minister Vladimir Putin has ordered security forces to find the masterminds of the twin suicide bombings that killed 39 people on the Moscow metro Monday.
In comments Tuesday on state television, Mr. Putin called the apprehension of the attack planners a matter of Russian national pride. He told law enforcement agencies to "drag them out of the depths of the sewer and into broad daylight."
Mr. Putin's tough talk came as grieving Russians piled flowers, lit candles and placed photographs of the dead near memorial plaques at two underground subway stations targeted in the attacks.
Elsewhere in the capital, the Russian Orthodox church held a vigil at the Cathedral of Christ the Savior. Television stations canceled all entertainment programming. Authorities say Moscow's metro was operating at full capacity.
Earlier Tuesday, President Dmitri Medvedev called for Russian courts and lawmakers to find new ways to strengthen anti-terror laws.
There has been no claim of responsibility for Monday's attacks. But authorities say the bombings in central Moscow were carried out by two women with links to Islamist insurgents in Russia's restive southern republics. The bombings are the first in the Russian capital in six years.
Russian media say police were searching Tuesday for two women and a man seen with the female bombing suspects on surveillance video shortly before the attacks occurred.
Last month, Chechen rebel leader Doku Umarov vowed to take the battle for Chechyna's independence to Russia's cities.