Islam Khalilov, a Moscow high school student from a Kyrgyz family, prevented the death toll from rising further by quickly opening the doors and guiding people trying to flee the concert hall during the shooting.

"I realized that if I didn't act, I would lose my life and many people around me would die. To be honest, I was very scared," Halilov, 15, told Moskva Online. 

"I was in the crowd and I went to the door to open it. I thought that someone coming from the stairs or the elevator would either throw a grenade or shoot at us. Thank God that didn't happen," Halilov said. 

Halilov, who started working at the Crocus Town Hall about a year and a half before the attack, said they were trained on what to do in an emergency. The 15-year-old said he knew how to conduct an evacuation thanks to this training.

Speaking to Ruptly, a subsidiary of Russian public broadcaster RT, Halilov said, "I don't see myself as a hero, this is part of my job. It is better to die yourself than to kill hundreds of people."

After the incident hit the media, famous Russian rapper Morgenshtern presented Halilov with a million rubles for his bravery. Spartak Moscow club, of which Halilov is a die-hard fan, also invited Halilov to meet the football players. 

Russian Commissioner for Children's Rights Maria Lvova-Belova said on Monday that Halilov and 14-year-old Artyom Donskov, who also works in the building where the concert hall is located, will receive an official letter of thanks from the government. 

The Russian Council of Muftis also said they would present Halilov with a medal of merit at Friday prayers at Moscow's Cathedral Mosque. 

On Friday, armed attackers wearing camouflage entered the Crocus Town Hall in the Moscow suburb of Krasnogorsk, opened fire on concertgoers and set the building on fire. At least 137 people were killed in the attack. Four of the 11 suspects detained were arrested on Sunday.

The radical Islamist terrorist organization ISIS claimed responsibility for the attack. ISIS's news agency Amaq shared footage of the attack on Sunday.