Moscow mayor Yury Luzhkov has thanked the residents of the Russian capital for restraint during Monday`s deadly subway blasts, according to RIA Novosti.

Two deadly suicide bombings hit the Moscow metro on Monday, killing at least 39 people and injuring more than 80. The blasts ripped through the rush-hour Lubyanka and Park Kultury stations with an interval of about 40 minutes.

"I want to not only apologize but also thank Muscovites for holding back their panic. It was hard and dangerous [in the subway]... [but] most people displayed restraint and understanding, and did not panic," Luzhkov said live on the TVC channel on Tuesday.

Moscow observed a day of mourning on Tuesday as Prime Minister Vladimir Putin vowed those behind the attack would be dragged "out of the sewers into the light of God."

The Federal Security Service (FSB) has said female suicide bombers were responsible for both blasts.

The explosions came four months after a terrorist bomb derailed a Moscow-St. Petersburg train, killing 27.

Russia has been fighting militants in the North Caucasus for almost two decades, including two brutal separatist wars in Chechnya. Analysts suggested that Monday`s attacks were revenge for a recent operation in Chechnya that saw the deaths of over 20 radical Islamic fighters.