- Mr Putin has spoken before of such a zone, but his public comments have not always reflected his aims in Ukraine.
- Ukraine says the front line has stabilised, admitting that Russia has occupied a number of border villages.
Russia is currently not seeking to capture Ukraine's second-largest city of Kharkiv, President Vladimir Putin has claimed.
"There are no such plans today," he said at the end of his visit to China.
But he stressed that Russian forces were advancing in the north-eastern Kharkiv region to create a "security zone" for Russia's border region.
Mr Putin has spoken before of such a zone, but his public comments have not always reflected his aims in Ukraine.
Ukraine says the front line has stabilised, admitting that Russia has occupied a number of border villages.
Russia launched its offensive in the region last week, and fierce street fighting has been reported for the past several days in the key town of Vovchansk near the Russian border.
On Friday, Ukrainian President Volodymyr Zelensky said Russian troops had only managed to advance to the first of Ukraine's three defensive lines in the region.
Similar comments were made by Ukraine's top commander Oleksandr Syrskyi, who said the "enemy has extended the active combat zone to nearly 70km (43 miles)" in the region.
Overnight, Kharkiv - which had a pre-war population of nearly 1.4 million - again came under Russian drone attack and shelling, local officials said. The technological and industrial hub lies about 30km from the Russian border.
Russia's full-scale invasion of its neighbour is now in its third year, and there are currently no signs that the war - the bloodiest conflict in Europe since World War Two - could end any time soon.
Winding up his state visit to China in the north-eastern city of Harbin on Friday, Mr Putin said that seizing Kharkiv was not part of Russia's current offensive in the region.
The Kremlin leader's public statements have often failed to reflect his actions in Ukraine. Notoriously, he denied Russia was on the cusp of a full-scale invasion before it took place in February 2022.
However, few analysts believe Russia has the military capacity to capture Kharkiv.
Mr Putin said the aim was to guarantee the security of Russia's border city of Belgorod, which has been frequently attacked by Ukraine's armed forces.
The Kremlin leader said that Ukraine was "firing right on the city centre, on the residential areas" of Belgorod.
"And I had said publicly that if this continued, we would be forced to create a security zone - a sanitary zone," he added.
Ukraine's military has not commented on Russia's claim that it was firing on residential parts of Belgorod. Kyiv has previously said it was hitting legitimate military targets in the region such as oil refineries.