The resumption on Thursday of the Nord Stream 1 pipeline at reduced capacity following a 10-day maintenance break comes after comments from Russia's foreign minister showed the Kremlin's goals had expanded during the five-month war.
Sergei Lavrov told state news agency RIA Novosti on Wednesday that Russia's military "tasks" in Ukraine now go beyond the eastern Donbas region.
Lavrov also said Moscow's objectives will expand further if the West keeps supplying Kyiv with long-range weapons such as the US-made High Mobility Artillery Rocket Systems (HIMARS).
"That means the geographical tasks will extend still further from the current line," he said, adding peace talks made no sense at the moment.
Kremlin spokesperson Dmitry Peskov later told RIA Moscow is not closing the door on talks with Kyiv despite Lavrov's comments.
Concern that Russian supplies of gas sent through the biggest pipeline in Europe could be stopped by Moscow prompted the European Union to tell member states on Wednesday to cut gas usage by 15 per cent until March as an emergency step.
"Russia is blackmailing us. Russia is using energy as a weapon," EU Commission President Ursula von der Leyen said, describing a full cut-off of Russian gas flows as "a likely scenario" for which "Europe needs to be ready".
Putin had earlier warned that gas supplies via Nord Stream were at risk of being reduced further.
Russia, the world's largest gas exporter, has denied Western accusations of using its energy supplies as a tool of coercion, saying it has been a reliable energy supplier.
As for its oil, Russia will not send supplies to the world market if a price cap is imposed below the cost of production, Interfax news agency quoted Deputy Prime Minister Alexander Novak as saying on Wednesday.
On the battlefront, the Ukrainian military has reported heavy and sometimes fatal Russian shelling amid what they said were largely failed attempts by Russian ground forces to advance.
In the previous 24 hours, Ukrainian forces said they had destroyed 17 vehicles, some of them armoured, as well as killing more than 100 Russian soldiers in the south and east.
The Russian-installed administration in the partially occupied Ukrainian region of Zaporizhzhia said Ukraine had conducted a drone strike on a nuclear power station there, but the reactor was not damaged.
Multiple blasts were also heard in the Russian-controlled southern region of Kherson overnight and into Thursday, Russian news agency TASS reported.
Reuters could not independently verify the reports.
Russia's invasion has killed thousands of people, displaced millions and flattened cities, particularly in Russian-speaking areas in the east and southeast of Ukraine. It has also raised global energy and food prices and increased fears of famine in poorer countries as Ukraine and Russia are both major grain producers.
The United States estimates that Russian casualties in Ukraine so far have reached around 15,000 killed and perhaps 45,000 wounded, CIA Director William Burns said on Wednesday.
Russia classifies military deaths as state secrets even in times of peace and has not updated its official casualty figures frequently during the war.
The US, whichon Tuesday had said it saw signs Russia was preparing to formally annex territory it has seized in Ukraine, promised that it would oppose annexation.
"Again, we've been clear that annexation by force would be a gross violation of the UN Charter, and we would not allow it to go unchallenged. We would not allow it to go unpunished," State Department spokesperson Ned Price said at a regular daily briefing on Wednesday.
Russia annexed Crimea from Ukraine in 2014 and supports Russian-speaking breakaway entities - the Donetsk and Luhansk People's Republics (DPR and LPR) - in those provinces, together known as the Donbas.
