A suspect in the mass shooting at a packed Russian concert venue said that he was promised the equivalent of about $5,400 to take part in the slaughter - half of which he lost trying to evade authorities, according to reports.

The Friday rampage at Crocus City Hall on the outskirts of Moscow killed at least 115 people and left many more wounded, Russian authorities said, as the Islamic State terror group claimed responsibility.

The suspect - one of 11 reportedly taken into custody - is not clearly identified by name, but seen restrained in an interrogation video posted to Telegram by Russia Today editor-in-chief Margarita Simonyan, the state-run outlet reported Saturday.

Speaking in what the outlet described as broken Russian, the man allegedly admitted that he "shot down...people" in exchange "for money," according to the report.

He reportedly said that he had been promised 500,000 rubles, the rough equivalent of $5,400, according to Russia Today.

Another state-run news outlet, Tass, reported that the man said he had been paid half up front, with the funds transferred onto his debit card.

He said he lost the card while trying to escape in the assault's aftermath, according to Tass.

The man said that he had been "listening to sermons... by a preacher" on Telegram for some time before the alleged masterminds of the attack contacted him on the app "around a month ago," according to Russia Today.

He reportedly said that the supposed organizers, whom he did not know directly, prepared an arms cache for him and his alleged fellow attackers.

Several assailants, clad in camouflage and armed with automatic weapons as well as incendiary devices, stormed the hall Friday, gunning down unsuspecting concertgoers and setting fire to the venue.