Russian president Vladimir Putin puts flowers down outside Tekhnologicheskiy Institute metro station in St. Petersburg, Russia, April 3, 2017. Reuters/Grigory Duko

Akbarzhon Dzhalilov has been identified as one of the suspects involved in the subway car explosion in the city of St. Petersburg Monday that killed 11 people and injured 50 others. Kyrgyzstan’s security service said Tuesday that the suspect is a Kyrgyz-born Russian citizen who was born in the city of Osh in 1995.

Authorities in St. Petersburg have declared three days of mourning as police probe the blasts, which took place in the metro car when it was between the Haymarket Square and Institute of Technology train stations. Kyrgyz state media said Tuesday the country's security service was "maintaining contact with the Russian secret service for further investigation." Authorities believe the suspect to be between 21 and 22 years of age, but they were not aware of his specific role in the bombing.

Russia’s Investigative Committee said it was probing an “act of terror” following the blasts, but no group has so far claimed responsibility for the attack. It is still unclear if the attack was a suicide bombing or whether the bomber escaped the scene when the explosion took place.

Read: ISIS Reacts To St Petersburg Deaths In Metro Explosions At Russian Subway Station

On Monday, President Vladimir Putin visited the scene of the attack and laid flowers at a makeshift shrine.

"I have spoken with representatives of our security agencies and the FSB Director. Our law enforcement and security agencies are working to establish the causes of the explosion and to provide their assessment of the situation. The city authorities, and if needed, the federal authorities, will take the necessary measures to help the families of those affected by the blast," Putin said in a statement. "The reasons behind it are not clear yet, and so it would be premature to speak about them. The investigation is ongoing. Of course, we always consider all scenarios, including accidental or criminal action, and above all, those of a terrorist nature. The ongoing investigation will soon provide answers regarding the causes of this tragedy."

While there is no confirmation on who was behind the attack, the Islamic State group and its followers were rejoicing the news of multiple deaths in the Russia metro blast.

"We ask Allah to bless the operation by the lions of the Caliphate, we ask Allah to kill the Crusaders," one message written in an internet forum called al-Minbar said. Another message made reference to "a metro to hell for the worshipers of the Cross."

The White House confirmed Monday that President Donald Trump spoke to Putin following the attack to pay his condolences.

"President Donald J. Trump spoke with President Vladimir Putin of the Russian Federation to condemn today's attack in St. Petersburg," the statement read.

Kremlin spokesman Dmitry Peskov also confirmed the phone call between the two leaders, saying: "In a telephone conversation with Vladimir Putin, Donald Trump extended deep condolences to the families of those who were killed in a barbaric terror attack in St. Petersburg subway, and asked to pass on words of encouragement to the Russian people."

"Presidents consider terrorism to be an evil that should be tackled in a concerted effort," Peskov added.