Russian President Vladimir Putin has called US President Donald Trump's move to impose more sanctions on Russia's oil industry an "unfriendly act" that will have little impact.
Washington has unveiled new sanctions on two of Russia's largest oil companies in response to the Kremlin's lack of commitment to ending the war in Ukraine.
On Thursday the European Union also heaped more economic sanctions on Russia as part of a broadened effort to choke off the revenue and supplies fuelling the war.
Mr Putin said that the "serious" US sanctions would have "certain consequences" for Russia, but maintained that they would not significantly impact its economy.
Ukrainian President Volodymyr Zelenskyy, who has long campaigned for the international community to punish Russia, welcomed the new restrictions.
"We waited for this. God bless, it will work. And this is very important," he said.
Despite US-led peace efforts in recent months, the war shows no sign of ending after nearly four years and European leaders are increasingly concerned about the threat from Russia.
Ukrainian forces have struggled to stem slow but steady Russian advances along a roughly 1,000-kilometre front that snakes along eastern and southern Ukraine.
China, India cut Russian oil imports
Some analysts say that the new sanctions could force Russia to further discount its oil on world markets to offset the perceived risk of US secondary sanctions.
They seem to already be having an effect.
Reuters has reported that major Chinese state oil companies had suspended purchases of seaborne Russian oil after the US sanctions on Rosneft and Lukoil, Moscow's two biggest oil companies.
The move comes as refiners in India, the largest buyer of seaborne Russian oil, are set to sharply cut their crude imports from Moscow to comply with the US sanctions.
A sharp drop in oil demand from Russia's two largest customers will strain Moscow's oil revenues and force the world's top importers to seek alternative supplies and push up global prices.
Refineries in India and China that continue to buy Russian oil to turn it into gasoline and diesel could potentially face US sanctions themselves, and so could their banks.
Despite welcoming the oil sanctions, Mr Zelenskyy said more pressure needed to be applied get Moscow to agree to a ceasefire.
After the August summit with Mr Putin Mr Trump dropped his demand for an immediate ceasefire in Ukraine and embraced Moscow's preferred option of going straight into a peace settlement negotiation.
But in recent days Mr Trump has reverted to the idea of an immediate ceasefire, something that Kyiv supports but which Moscow has no interest in.
Russia says it opposes a ceasefire because it believes it would only be a temporary pause before fighting resumes after giving Ukraine time and space to rearm.
Lithuanian president: Russian military planes violated airspace
Russian military planes briefly violated Lithuania's airspace on Thursday evening, Lithuanian President Gitanas Nauseda said.
Lithuania's foreign ministry planned to summon Russian embassy representatives in the Lithuanian capital of Vilnius to protest the violation, Mr Nauseda said in a post on X.
"This is a blatant breach of international law and territorial integrity of Lithuania," Nauseda wrote on X.
"Once again, it confirms the importance of strengthening European air defence readiness."
There was no immediate comment from Moscow.
Baltic nations have been on heightened alert over neighbouring Russia's activity in Ukraine.
In recent weeks a series of mysterious drone incidents and airspace violations by Russian war planes have fuelled concerns that Mr Putin might be testing NATO's defensive reflexes.
Moscow denies probing NATO's defences.
Lithuania's armed forces said in a statement that two Russian military aircraft flew about 700 metres into Lithuanian airspace.
The SU-30 aircraft and IL-78 refuelling aircraft flew away after roughly 18 seconds.
AP/Reuters