US National Security Advisor Jake Sullivan, said in a CNN interview on Sunday that Russian President Vladimir Putin was "frustrated by the fact that his forces are not making the kind of progress that he thought they would make against major cities."

This frustration, according to Sullivan, is making Putin lash out, to "cause damage in every part of the country."

Kremlin Spokesperson Dmitry Peskov replied to these statements, saying that such US and EU officials who make similar statements seem to want to push Russia "to storm major cities in Ukraine in order to lay the blame on our country for the deaths of civilians," calling this position "provocative".

Peskov further added that military operations will undoubtedly lead to heavy civilian losses, and the operation was planned with this exact issue in mind to avoid such losses.

The UN said on Sunday that so far at least 596 Ukrainian civilians have been killed, and 1,067 were injured.

Regarding the humanitarian situation and the evacuation of refugees, Putin said on March 3 that Moscow has established humanitarian corridors and provided transport so that civilians are given the opportunity to leave. 

He added that Ukraine's nationalists are not allowing them to do so. Rather, they are gathering residents in apartment buildings, and placing weapons on the lower and upper floors, "only the Nazis treated civilians so inhumanly", Putin asserted.

"Nationalist and neo-Nazi formations, and among them there are foreign mercenaries, including from the Middle East, hide behind civilians as a human shield. I have already said that there is absolutely objective photographic data of how they place heavy military equipment in residential areas of cities."