In Kiev, fierce street fighting has taken place since Russia began its invasion of Ukraine.

Buildings have been demolished by robot and missile attacks at the same time as ground troops have marched through the city.

On Sunday, Russia also launched an offensive against Ukraine's second largest city, Kharkiv.

Also there with violent street fights as a result.

According to former Lieutenant Colonel Jörgen Elfving, fighting in an urban environment probably does not belong to Russia's original strategy.

- That it does not go according to plan for Russia is obvious.

There is information that says that the Kremlin is worried and even shocked that it is going so slowly and that losses have been added, he says in the Morning Studio.

"Failed to establish air supremacy"

According to Katarina Engberg, security policy analyst, the lack of control over the air and tougher resistance than expected are some of the explanations for the development.

- An important factor is that the Russian side has not succeeded in establishing air supremacy, she says Morgonstudion.

- This means that you have to rely on the fighting force in the form of tanks and army combat power, she continues.

"Anxiety, disorder and panic"

According to Jörgen Elfving, the picture of what is happening in Kiev is that Russian units are sending in smaller units of Russian special forces.

- Partly to create anxiety, chaos and panic.

But also the purpose is to take care of the political leadership, especially then the president, he says.

What does it mean that the battles move into the urban environment?

- It has consequences.

If you plan a regular attack into buildings, it requires very large resources from the attacker.

It will also lead to big losses when you are forced to move from block to block.

And the end result is that the city in question is laid in gravel and ash.

Katarina Engberg believes that the fighting can be protracted and cause great devastation in the cities that are invaded.

- Then you get city battles that destroy parts of the city.

It will look like Grozny in Chechnya or Aleppo, she says.

- What is important militarily in this type of operation is that you have endurance over time.

You have to provide all people with food, you have to provide the platforms you have in place with fuel and ammunition.

That is a weakness in itself.