Indian Prime Minister Narendra Modi called for a detailed investigation into last week’s major security breach of parliament, countering demands from opposition parties for a debate in the chamber on the incident.

“What happened is very serious,” Modi told the Dainik Jagran newspaper in an interview published on Sunday, his first comments on Wednesday’s breach.

“There is no need to debate this, there should be a detailed investigation into this.”

Police arrested six people, filing terrorism charges against four, after a man jumped into the lower house chamber while members were in session, shouted slogans and set off a smoke canister. A second man tried to follow him.

Both were caught by lawmakers and security personnel, and taken away. The incident occurred on the 22nd anniversary of an attack on the parliament complex in which more than a dozen people were killed, including five gunmen.

Members of parliament told local media the two men had chanted slogans, including “dictatorship won’t be accepted”.

Families of some of the four suspects told media they had expressed annoyance at not being able to find jobs for a long time.

Fourteen lawmakers have been suspended for disrupting parliament proceedings by demanding a discussion and a statement from Home Minister Amit Shah on the incident.

The speaker of the lower house of parliament has announced a security review, and the government has said opposition parties are trying to politicise the incident.