A Ukrainian presidential aide said on Monday a demilitarised zone of 100-120 km (62-75 miles) should be established inside Russia along the border with Ukraine as part of a post-war settlement.
The zone would be necessary to protect Ukrainian regions from Russian attacks, presidential adviser Mykhailo Podolyak wrote on Twitter.
"The key theme of the post-war settlement should be the establishment of safeguards to avoid the recurrence of aggression in the future," he wrote.
He made his remarks after the governor of Russia's Belgorod region, which borders Ukraine, called in televised comments for the annexation of Ukraine's Kharkiv region to stop Ukrainian cross-border shelling.
Moscow says Ukraine has stepped up drone and sabotage attacks against targets inside Russia as it prepares for the offensive. Kyiv has denied firing at targets inside Russia, saying it is fighting a defensive war on its own territory.
To ensure the safety of residents in several frontline Ukrainian regions, he wrote, "it will be necessary to introduce a demilitarization zone of 100-120 km on the territory of Belgorod, Bryansk, Kursk, and Rostov republics."
The reference to the Russian regions as republics appeared to be a nod towards Moscow backing separatist entities calling themselves "people's republics" in Ukraine's Donetsk and Luhansk regions which border Russia.
Podolyak said the demilitarised zone could initially have an international presence to control it.
"Probably, at the initial stage with a mandatory international control contingent," he wrote.
(Reporting by Max Hunder, Editing by Timothy Heritage)
