Kremlin spokesman Dmitry Peskov said that "(Ukrainian President Volodymyr) Zelenskyy knows when it may end. It may end tomorrow if he wishes so.''
The Ukraine war has deteriorated relations between Russia and much of the rest of the world, but limited cooperation continues in some areas, such as exchanges of prisoners.
On Thursday, in a dramatic swap that had been in the making for months, Russia freed American basketball star Brittney Griner while the United States released a jailed Russian arms dealer.
The Kremlin has long said that Ukraine must accept Russian conditions to end the fighting, now in its tenth month. It has demanded that Kyiv recognize Crimea, a Ukrainian peninsula that Moscow illegally annexed in 2014, as part of Russia and also accept Moscow's other land gains in Ukraine.
Zelenskyy and other Ukrainian officials have repeatedly rejected those conditions, saying the war will end when the occupied territories are retaken or Russian forces leave them.
In an acknowledgement that it's taking longer than he expected to achieve his goals in the conflict, Putin said Wednesday that the fighting in Ukraine "could be a lengthy process.'' He described Moscow's land gains as "a significant result for Russia,'' saying, for example, that the Sea of Azov "has become Russia's internal sea.''
During a conference call with reporters, Peskov said Moscow wasn't aiming to grab new land but will try to regain control of areas in Ukraine from which it withdrew just weeks after incorporating them into Russia in hastily called referendums, which Ukraine and the West reject as illegal shams.
After earlier retreats from the Kyiv and Kharkiv areas, last month Russian troops left the city of Kherson and parts of the Kherson region, one of the four illegally annexed Ukrainian regions.
"There are occupied territories in several new regions of the Russian Federation that need to be liberated,'' Peskov said.
Putin vowed Thursday to achieve the declared goals in Ukraine regardless of the Western reaction.
"All we have to do is make a move and there is a lot of noise, chatter and outcry all across the universe. It will not stop us fulfilling combat tasks,'' Putin said.
He described Russian strikes on Ukraine's energy facilities and other key infrastructure as a legitimate response to an Oct. 8 truck bombing of a key bridge linking Crimea with Russia's mainland, and other attacks the Kremlin claimed Ukraine carried out.
Putin also cited Ukraine's move to halt water supplies to the areas in eastern Ukraine that Russia controlled.
"There is a lot of noise now about our strikes on the energy infrastructure,'' Putin said at a meeting with soldiers whom he decorated with the country's top medals.
"Yes, we are doing it. But who started it? Who struck the Crimean bridge? Who blew up power lines from the Kursk nuclear power station? Who is not supplying water to Donetsk?''
While stopping short of publicly claiming credit for the attacks, Ukrainian officials welcome their results and hint at Ukrainian involvement.
While earlier acknowledging delays in achieving the goals of what he calls his "special military operation,'' on Thursday, Putin praised the Russian air force's performance as "highly efficient.''
"The air force has done very well,'' he said. "It has contributed significantly to the efficiency of the army's action.''
Despite its massive numerical advantage, the Russian air force has failed to suppress Ukraine's air defenses and win full control of Ukrainian skies. It has continued to suffer losses from attacks by Ukrainian fighter jets and air defense batteries.
Heavy fighting continued Thursday, mostly in the regions Russia annexed. Zelenskyy's office said 11 civilians were killed and 17 wounded in Ukraine on Wednesday.
The Donetsk region has been the epicenter of the recent fighting. Russian artillery struck the town of Yampil, northeast of Sloviansk, during the distribution of humanitarian aid to civilians,
Ukrainian officials said. Buildings in the city center, in addition to the market and bus station, were damaged in Kurakhove, some 35 kilometers (22 miles) west of the regional capital, Donetsk, officials said.
More than ten cities and villages in the region were shelled, including the town of Bakhmut, which has remained in Ukrainian hands during the war despite Moscow's goal of capturing the entire annexed Donbas region bordering Russia.
Swedish newspaper Svenska Dagbladet said a Swedish aid worker was killed Wednesday in a car accident while leaving Bakhmut.