As Putin asked the FSB to bolster security, Moscow said it is open to peace talks, but will not give up annexed regions.

Ukraine’s military said on Tuesday that Russia was shelling settlements around Bakhmut, which had a pre-war population of approximately 70,000 but now lies in ruins after months of intense trench warfare.

“Over the past day, our soldiers repelled more than 60 enemy attacks,” the military said early on Tuesday, including on the villages of Yadhidne and Berkhivka just north of Bakhmut.

Russian President Vladimir Putin instructed the Federal Security Service (FSB) on Tuesday to bolster forces in the four regions – currently only partially controlled by his forces – and also to counter what he described as growing espionage and sabotage operations against Russia by Ukraine and the West.

He was speaking after a Russian regional governor said a drone had crashed near a natural gas distribution station on Tuesday in an apparent failed attack near the town of Kolomna, just 110km (68 miles) southeast of Moscow.

Kremlin spokesman Dmitry Peskov repeated Moscow’s stance that it is open to peace negotiations, but Kyiv and its Western allies must accept Russia’s annexation of four Ukrainian regions – Donetsk, Luhansk, Kherson and Zaporizhia – after referendums last September that Kyiv and the West said were illegal.

“The constitution of the Russian Federation exists and cannot be ignored. Russia will never be able to compromise on this, these are important realities,” Peskov told reporters.

Meanwhile, the US undersecretary of defence for policy, Colin Kahl, described the front line in Ukraine as a “grinding slog” and said he did not expect Russia to be able to make significant territorial gains in the near term.

“So you may see small portions of territory change hands in the coming weeks and months. I do not think that there’s anything I see that suggests the Russians can sweep across Ukraine and make significant territorial gains anytime in the next year or so,” Kahl told a House of Representatives hearing.

The US also said on Tuesday that it will not hesitate to target Chinese companies and individuals if Beijing violates US sanctions on Russia over the Ukraine war, Secretary of State Antony Blinken said.

If China provides lethal aid to Moscow, it will be a severe problem for Beijing’s relationship with countries worldwide, Blinken told reporters during a trip to Kazakhstan and Uzbekistan.

Ukraine’s head of military intelligence, however, has brushed aside claims that China is considering furnishing arms to Russia, telling US media that he saw no “signs that such things are even being discussed”, AFP reported.

The Kremlin has said Moscow is open to peace talks, but it is not willing to give up the four annexed regions.

Also on Tuesday, the EU took to planning to extend its gas consumption reduction measures into next winter to replenish stocks, the bloc’s energy ministers have said.

The EU regulation adopted last year expires at the end of March, the EU’s energy commissioner Kadri Simson said, adding that the energy commission considers “continuing demand reduction a no-regret option”.

EU member states will have to agree to any new target on reduction for next winter, with Germany, the EU’s biggest economy, calling for a target higher than 15 percent.