Earlier in the day, media reports emerged of a bomb exploding near the institute, causing a fire to break out at the laboratories. The flames were later extinguished by firefighters, with no casualties reported.
"At the moment, we can confirm that this was a criminal act, but we have no information to indicate that this was a terrorist attack. We also have no evidence that there was a bomb, at the moment we are investigating a case of criminal arson," the spokesperson told RIA Novosti.
According to the spokesperson, the laboratories suffered "extensive damage" in the fire.
"Two people have been detained," the spokesperson added.
Earlier in the day, Belgian Justice Minister Koen Geens wrote on Twitter that the authorities were investigating an incident of criminal arson at the Criminology Institute, adding that no conclusions could be drawn at that stage.
Belgian Justice Minister says the cause of a fire outside of a crime lab in Brussels appears to be "criminal." https://t.co/g5WDEpY2y9
— Rachel Katz (@RKatz) 29 августа 2016 г.
Belgium's terror alert level remains high since bomb attacks on the Brussels Airport and a metro station that killed 32 and injured over 300 people in March. The Islamic State jihadist group, outlawed in many countries including Russia, claimed responsibility for the attacks.