Originally Published: 29 MAR 22 10:37 ET

Updated: 29 MAR 22 11:07 ET

By Nathan Hodge, Daria Markina and Lindsay Isaac, CNN

(CNN) -- Russia said it would "drastically reduce" its military assault on the Ukrainian cities of Kyiv and Chernihiv after talks took place between representatives of the two nations on Tuesday, as Ukrainian officials claimed Russian troops were withdrawing from battlefronts there because they had failed in their goals.

The Russian defense ministry has decided to "radically, at times, reduce military activity" in the direction of Kyiv and Chernihiv, deputy defense minister Alexander Fomin said, state media RIA reported. The ministry's Telegram channel also said that Moscow would "drastically reduce military activity" in the cities.

The move follows talks between Russian and Ukrainian delegations in Istanbul, Turkey on Tuesday.

Fomin told reporters that the ongoing discussions regarding the "neutrality and non-nuclear status of Ukraine" had contributed to the decision. More details on the steps to reduce hostilities will follow after the Russian delegation returns from Istanbul, Fomin said in remarks carried by Russian state news agency TASS.

Ukraine echoed the announcement regarding the reduction in military action, saying some Russian troops were pulling back from Kyiv and Chernihiv.

"The Russian enemy did not meet the goal of its offensive operation," the General Staff of the Armed Forces of Ukraine said in an official Facebook update Tuesday, adding that "certain units" of Russia's military were withdrawing from battlefronts in the cities.

However it warned of a "high risk" of Russian troops attacking military and civilian infrastructure. The Russian military, it claimed, was struggling to reinforce and rotate in new soldiers, due to the "refusal of personnel to participate in the so-called special operation," and are "not able to staff even one battalion-tactical group."

However, enough progress was made during Tuesday's talks between the Russian and Ukrainian delegations to allow Russian President Vladimir Putin and Ukrainian counterpart Volodymyr Zelensky to meet, Ukrainian presidential adviser Mykhailo Podolyak has said.

Speaking in Istanbul after the talks between the two sides ended, Podolyak said there was now a "likelihood" that the two presidents may meet."We have documents prepared now which allow the presidents to meet on a bilateral basis," he said.

Talks between the two parties will "continue online 24/7," Podolyak said, adding that Ukraine needs "clear legal wording."

Russian state news agency RIA-Novosti, citing the Russian delegation, also reported the possibility of a meeting between Putin and Zelensky. The head of the Russian delegation, presidential aide Vladimir Medinsky, called the negotiations "constructive," RIA reported.

The United States also believes Russia is executing a major strategy shift and withdrawing some forces from the area around Kyiv, two senior US officials told CNN on Tuesday.

The Russian forces are now pulling back in some areas of the north to focus on gains in the south and east, the US believes. The US has already observed these movements underway, including Russian Battalion Tactical Groups (BTGs) leaving the surrounding areas around Kyiv, according to the US intelligence.

In the US view, this is not a short-term adjustment to regroup, but a longer-term move as Russia comes to grips with failure to advance in the north.

The US assesses Russia will cover their retreat with air and artillery bombardment of the capital, one of the officials said. US officials caution that Russia could always reverse again if the battle conditions allow.

Brig. Gen. Kyrylo Budanov, the head of Ukraine's Defense Intelligence Agency, said Russia's operations around Kyiv had failed and it was now impossible for the Russian army to overthrow the Ukrainian government. Putin's war was now focused on the south and the east of the country, he said.

"There is reason to believe that he is considering a 'Korean' scenario for Ukraine," said Budanov. "That is, [Russian forces] will try to impose a dividing line between the unoccupied and occupied regions of our country. In fact, it is an attempt to create North and South Korea in Ukraine."

The mayor of of Chernihiv, Vladyslav Atroshenko, told CNN that between 300 and 400 people, mostly civilians, had been killed in the last three weeks.

Speaking to CNN on Tuesday, Atroshenko said: "We don't have the exact figure because we can only count those who died in a hospital, but if people die from an explosion, we cannot always identify them."

Chernihiv, which lies about halfway between Kyiv and the Russian border, has endured intense shelling in recent weeks. Videos geolocated by CNN show heavy damage in civilian areas. On Saturday the mayor announced the city was surrounded by Russian forces, leaving no safe pathways in or out.