Russian President Vladimir Putin on Saturday defended an unprecedented crackdown on dissenting voices in Russia at a time of “armed conflict” with Ukraine, urging everyone to follow “certain rules.”

“It’s the year 2023, and Russia is engaged in an armed conflict with a neighbour. And I think that there should be a certain attitude towards people who harm us inside the country,” Putin told reporters in Saint Petersburg.

“We must keep in mind that in order for us to achieve success, including in a conflict zone, everyone needs to follow certain rules,” Putin added.

The Russian president was responding to a question from a reporter who asked him to comment on the recent jailing of a theatre director and a sociologist.

“The people were arrested for the words they said or wrote. Is this normal?” Andrei Kolesnikov, a veteran reporter for Kommersant daily newspaper, asked Putin.

This week Russian authorities detained prominent sociologist Boris Kagarlitsky, 64, and accused him of calling for terrorism online.

In May, a Moscow court ordered the arrest of theatre director Yevgeniya Berkovich, 38, on charges of “justifying terrorism” over an award-winning play about Russian women recruited online to marry radical Islamists in Syria.

Putin said he did not know who Kagarlitsky and Berkovich were.

“I hear these names for the first time and do not really understand what they did or what was done to them,” Putin said. “I’m just telling you about my overall attitude towards the problem.”

Criticism of Moscow’s offensive in Ukraine has been outlawed and most prominent members of the liberal opposition are either in jail or in exile.

Last week authorities detained former separatist commander and nationalist blogger Igor Girkin on accusations of “extremism” after he criticised Putin.

Elsewhere, a Russian rocket attack killed one civilian and injured five more in the northeastern city of Sumy late on Saturday, Ukraine’s interior ministry said.

“During the evening of July 29, an enemy missile hit an educational institution,” the ministry said on Telegram. “At least one civilian was killed and 5 civilians were wounded.”

Russian forces crossed into the Sumy region soon after Moscow invaded Ukraine on February 24 last year, but Ukrainian forces took back control of the region a few weeks later.

Ukraine’s national police posted video on Telegram showing one person being carried away in a stretcher, a building in rubble and trees splintered.

Reuters could not verify the details of the report.