Pictures: Suicide bombings on Moscow

Passengers stand in the doorway of a metro carriage near flowers in memory of victims of a terrorist bomb blast inside the Lubyanka metro station in Moscow, Russia.  (ANDREY SMIRNOV/AFP/Getty Images)

Malaysian exchange student Er Chi Kent who was injured in the metro blast at Park Kultury, sits in a Moscow hospital. Two female suicide bombers blew themselves up on packed metro trains in Moscow on Monday, killing at least 38 people near the ex-KGB headquarters and Gorky Park, in attacks blamed on Islamists.  (STR/AFP/Getty Images)

Russian police and emergency workers stand guard outside the entrance to Park Kulturi metro station in Moscow after two explosions during the early morning rush hour in metro stations killed at least 34 people. Moscow chief prosecutor Yury Syomin said that two women suicide bombers, wearing belts with explosives, caused the twin blasts.  (OXANA ONIPKO/AFP/Getty Images)

Bomb-sniffing Russian police dogs await deployment at the Park Kultury metro station in Moscow. Thirty-eight people were killed in double suicide blasts on the Moscow metro system, the emergency situations ministry said, after more victims died in hospital.  (OXANA ONIPKO/AFP/Getty Images)

A Russian policeman stands guard as workers with equipment enter the Park Kultury metro station in Moscow. Two female suicide bombers blew themselves up on packed metro trains in central Moscow’s morning rush hour, killing at least 37 people in the deadliest attacks in the Russian capital for six years  (OXANA ONIPKO/AFP/Getty Images)

An ambulance sits parked near a puddle of blood at the Park Kultury metro station in Moscow after two explosions during the early morning rush hour in metro stations killed at least 35 people. Moscow chief prosecutor Yury Syomin said that two women suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (Photo by OXANA ONIPKO/AFP/Getty Images)

Russian police carry equipment and stand guard near the Lubyanka metro station in Moscow on March 29, 2010 after two explosions during the early morning rush hour in metro stations killed at least 34 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (Photo by ANDREY SMIRNOV/AFP/Getty Images)

Russian police stand guard near the Lubyanka metro station in Moscow on March 29, 2010 after two explosions during the early morning rush hour in metro stations killed at least 34 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (Photo by ANDREY SMIRNOV/AFP/Getty Images)

Russian riot police run near the Lubyanka metro station in Moscow on March 29, 2010 after two explosions during the early morning rush hour in metro stations killed at least 34 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (AFP/Getty Images)

Russian police stop traffic to clear the way for emergency workers near the Lubyanka metro station in Moscow on March 29, 2010 after two explosions during the early morning rush hour in metro stations killed at least 34 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (AFP/Getty Images)

A helicopter lands at the Lubyanka metro station near the Federal Securtiy Services (FSB) building in Moscow on March 29, 2010 after two explosions during the early morning rush hour in Moscow metro stations killed at least 35 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (Photo by OLEG KASHIN/AFP/Getty Images)

A helicopter lands at the Lubyanka metro station near the Federal Securtiy Services (FSB) building in Moscow on March 29, 2010 after two explosions during the early morning rush hour in Moscow metro stations killed at least 35 people. Moscow chief prosecutor Yury Syomin said that suicide bombers, wearing belts with explosives, caused the twin blasts -- one at Lubyanka station and the other at Park Kulturi station.  (Photo by OLEG KASHIN/AFP/Getty Images)

Russian Prime Minister Vladimir Putin participates in a video conference with officials in Moscow. The blasts that killed 37 during morning rush hour in central Moscow came after the Kremlin with much fanfare ended its decade-long military crackdown in Chechnya last April, claiming stability had returned to the volatile region.  (ALEXEY NIKOLSKY/AFP/Getty Images)