An First Information Report (FIR) was filed against unknown persons on Saturday after explosive materials were found in Uttar Pradesh Assembly.
The case has been registered under Unlawful (Activities) Prevention 2004, and Explosive Substances Act 1908.
Uttar Pradesh's Inspector General of the Anti Terrorist Squad (ATS), Aseem Arun has said the discovery of the explosive powder -- Pentaerythritol tetranitrate (PETN) - hinted the possibility of a terrorist activity.
"We will scan through the CCTV footage and will do a detailed investigation of the spot today," Aseem Arun said.
Meanwhile, Chief Minister Yogi Adityanath has called for a National investigative Agency (NIA) probe.
"The packet of the explosive was found under the chair of the Opposition's leader. It was 150 gm of PETN. 500 gm of PETN is enough to blow the whole Assembly off. This shows the severity of the situation. I suggest that everybody present in the Assembly should be investigated by the police and that the NIA should investigate into the matter," he said.
"It's unfortunate that the largest Assembly of the country doesn't have a QRT," he added.
Adityanath also said that this incident could be in connivance with a terrorist or militant group and that the security of the state and the country is paramount.
Earlier, 60 grams of suspicious white powder was found in the UP Assembly during an ongoing session, which was later sent to forensic lab for testing.