Russian President Vladimir Putin said on Monday that Ukraine's biggest attack on Russian territory since the start of the conflict was aimed at improving Kyiv's negotiating position ahead of the possible peace talks and at slowing the advance of Russian forces, and ordered his army to "dislodge" Ukrainian troops.

"One of the obvious goals of the enemy is to sow discord, strife, intimidate people, destroy the unity and cohesion of Russian society," Putin told a televised meeting with government officials.

"The main task is, of course, for the defense ministry to dislodge the enemy from our territories," he said.

Kyiv launched a surprise offensive into southwestern Russia's Kursk region last Tuesday, capturing over two dozen settlements in the most significant cross-border attack on Russian soil since World War II.

Putin, in his most detailed public remarks on the incursion to date, said Ukraine "with the help of its Western masters" was trying to improve its position ahead of possible talks.

He questioned what negotiations there could be with an enemy he accused of firing indiscriminately at Russian civilians and nuclear facilities.

"The enemy will certainly receive a worthy response," he said, noting that he expected further Ukrainian attempts to destabilize Russia's western border.

Ukrainian President Volodymyr Zelensky said that Ukraine's cross-border assault was a matter of security for Ukraine and that Kyiv had captured areas from where Russia launched strikes.

His top commander, Oleksandr Syrskyi, said Ukraine controlled 1,000 square kilometers of Russian territory, far larger than the figures given by Russian officials.

On Tuesday, Ukrainian Foreign Ministry spokesperson Georgiy Tykhy told a news conference that the sooner Russia agreed to a "just peace", the sooner it would stop its cross-border raids.

Stretching troops

A Ukrainian official told AFP over the weekend that the operation was aimed at stretching Russian troops and destabilizing the country after months of slow Russian advances across the front line.

Authorities in Kursk announced they were widening their evacuation area to include the Belovsky district, home to some 14,000 residents.

The acting governor of Kursk, Alexei Smirnov, said Ukraine controlled 28 settlements in the region, and the incursion was about 12 km deep and 40 km wide.

In the Kursk region alone, 121,000 people had already left or been evacuated and another 59,000 were in the process of being evacuated.

Ukrainian forces in Kursk were trying to encircle Sudzha, where Russian natural gas flows into Ukraine, while major battles were underway near Korenevo, about 22 km from the border, and Martynovka.

Video from social media and verified by Reuters showed Ukrainian soldiers raising their flag in the Russian village of Guevo, in Kursk.

Smirnov also issued a missile warning, saying people needed to take shelter in rooms without windows and with solid walls.

Temporary accommodation has been prepared, he said.

As Russia is evacuating residents from a second border region, the Belgorod region which borders Kursk, some 11,000 civilians were evacuated.

Belgorod Governor Vyacheslav Gladkov said the whole region was under a missile alert, and told people to shelter in their basements.

But he added he was "sure that our servicemen will do everything to cope with the threat that has arisen".