White powder was found wrapped in paper close to the seat of the Leader of the Opposition on July 13.

Uttar Pradesh Chief Minister Yogi Adityanath on Friday called for an NIA probe after an explosive substance was found near one of the benches of the State Assembly in a major security lapse.

The suspicious white powder was discovered by Vidhan Sabha staff on Thursday and had apparently been missed by the House security and dog squads.

A forensic probe of the substance revealed it to be Pentaerythritol tetranitrate (PETN), Mr. Adityanath said in the Assembly on Friday.

The white packet containing the substance weighed 150 grams. The plastic packet was found under the chair of Ram Kobind Chaudhary, the Leader of the Opposition, Mr. Adityanath informed the House.

The forensics arrive in front of Vidhan Sabha at Lucknow on Friday. | Photo Credit: Rajeev Bhatt

Expressing concern over the security lapse, the Chief Minister said he has called for an urgent meeting on Assembly security.

"PETN found in the Vidhan Bhawan proves that some people are up to some mischief. We need to respond strongly to their mischief. That is why it is necessary for the NIA to probe this and unmask such elements," Mr. Adityanath said.

Mr. Adityanath also said that a proper police verification should be conducted of the Assembly staff as such lapses could be potentially dangerous.

"It is difficult to trace this explosive. Only when officials physically check it that it can be traced," said the chief minister.

"It was 150 gm of PETN. 500 gm of PETN is enough to blow the whole Assembly off,"

Mr. Adityanath said, ruing the absence of a Quick Response Team in the State even as he speculated that the incident could have been executed in connivance with a militant or terrorist group.

Uttar Pradesh Assembly Speaker Hriday Narain Dixit said Provincial Armed Constabulary (PAC) and Quick Response Teams will be deployed at Assembly premises.