Photo taken on Dec. 30, 2013 shows the blast site of the trolleybus in Volgograd, Russia. (Xinhua/RIA Novosti)

President Vladimir Putin ordered the National Anti-Terrorism Committee (NAC) to tighten security throughout Russia on Monday after two blasts in Volgograd left at least 32 people dead.

Several presidential instructions were specially on Volgograd, some 900 km southeast of Moscow, said the committee.

Russian Deputy Emergency Situations Minister Vladimir Stepanov said the blasts, which occurred Sunday in a railway station and Monday on a trolley bus, have killed 32 people and injured 72 others. Among the victims, 17 were killed in the Sunday blast and 15 in the Monday explosion.

The NAC said five militants were killed on Monday in the North Caucasian republics of Kabardino-Balkaria and Dagestan, with explosives destroyed in the Ingush republic.