Lok Sabha Speaker Om Birla on Wednesday said the security lapse in the House is being thoroughly probed and called a meeting of MPs from all parties later in the day to address their concerns over the matter.

As the House met at 2 pm, amid concerns raised by various leaders, including on the threat video recently released by designated terrorist Gurpatwant Singh Pannu, Speaker Birla said it will not be right to discuss the issue in the House.

In a major security breach on the 22nd anniversary of Parliament terror attack, two intruders jumped into the Lok Sabha chamber from the public gallery during Zero Hour and released yellow gas from canisters and shouted slogans before being overpowered by MPs.

Around the same time, two persons, including a woman, also sprayed coloured gas from canisters while shouting slogans outside Parliament premises.

Birla informed the House that four persons have been arrested - two from inside the House, and two from outside Parliament in connection with the incident.

He said the Lok Sabha is conducting a probe and the Delhi Police has also been instructed to do so.

The smoke that was released by the intruders appeared to be harmless in the initial probe, he said, adding it looked like it was sprayed to create sensationalism.

Speaker Birla called a meeting of MPs later in the day, where he said all concerns will be addressed.