"The key topic of the post-war settlement should be the establishment of safeguards to prevent a recurrence of aggression in the future," Podolyak tweeted, adding that it will be necessary to introduce a demilitarization zone of 100-120 km to ensure security for residents of Kharkov, Chernigov, Sumy, Zaporozhye, Lugansk and Donetsk regions and protect them from shelling.
The presidential aide suggested creating such a zone on the territory of Russia's Belgorod, Bryansk, Kursk and Rostov regions.
"Probably with a mandatory international control contingent at the first stage," Podolyak wrote.
"Such statements by Ukrainian officials confirm their complete detachment from reality and their persistent hostile aspirations," a Sputnik source in Moscow said, commenting on Podolyak's remarks.
In late February, Ukrainian military intelligence chief Kyrylo Budanov said that Ukraine was considering the creation of a security zone along its 1991 border with Russia that would cover territory up to 100 kilometers deep.
In December 2022, Ukrainian President Volodymyr Zelensky said that the only way to end hostilities in Ukraine was for Russia to withdraw its troops to the 1991 borders.