Moscow hit back at Western capitals Wednesday for sanctioning senior Russian officials over the poisoning of Kremlin critic Alexei Navalny, warning its foes "not to play with fire".

The Kremlin accused Washington and Brussels of interference after the US and the EU introduced fresh penalties Tuesday over Navalny, who was jailed last month on returning from Germany where he was recovering from exposure to a nerve agent.

Alexei Navalny has gained popularity for his investigations into the wealth of Russia's elites
Alexei Navalny has gained popularity for his investigations into the wealth of Russia's elites AFP / Kirill KUDRYAVTSEV

The sanctions further erode ties between Moscow and the West following Russia's annexation of Crimea in 2014.

"We believe such measures are absolutely unacceptable because they significantly damage already bad relations" with Washington and Brussels, Kremlin spokesman Dmitry Peskov told reporters Wednesday.

He said the new sanctions amounted to "interference" in Russia's domestic affairs and vowed to take action in response, without specifying measures.

The sanctions further erode ties between Moscow and the West since Russia's annexation of Crimea in 2014
The sanctions further erode ties between Moscow and the West since Russia's annexation of Crimea in 2014 AFP / Alexander NEMENOV

Peskov's comments echoed foreign ministry spokeswoman Maria Zakharova who warned the West "not to play with fire" and said Russia would respond according to "the principle of reciprocity.

"We will continue to systematically and resolutely defend our national interests and rebuff aggression," she said in a statement published late Tuesday.

Navalny might be sent to the penal colony N2 to serve a two-and-a-half year prison term for violating parole
Navalny might be sent to the penal colony N2 to serve a two-and-a-half year prison term for violating parole AFP / Dimitar DILKOFF

The sanctions announced Tuesday by Washington signal a harder line from President Joe Biden and target several individuals within Russia's security sector, including Federal Security Service (FSB) head Alexander Bortnikov.

Kremlin critic Alexei Navalny will serve two and a half years in Russian prison for violating parole. He is expected to spend time in penal colony no.2 in the provincial town of Pokrov, 100 kilometres east of Moscow. It is part of a sprawling network of s
Kremlin critic Alexei Navalny will serve two and a half years in Russian prison for violating parole. He is expected to spend time in penal colony no.2 in the provincial town of Pokrov, 100 kilometres east of Moscow. It is part of a sprawling network of some 684 work colonies that today holds some 393,000 prisoners. AFPTV / Nikolay KORZHOV

But Peskov again denied Russian involvement and said claims that the FSB was involved in a poisoning attack were "outrageous".

Navalny maintains his near fatal attack was carried out by the FSB on the orders of Russian President Vladimir Putin, a claim vehemently denied by the Kremlin.

On Wednesday, he joked that "everything is fine", in his first message from the Kolchugino detention centre northeast of Moscow.

Although Navalny is deprived of books and news from outside, an Instagram message was nevertheless posted in which he quipped that "the only entertainment is haute cuisine experiments."

That included drying bread to make croutons with his cellmates.

"We are having a competition of two cuisines: street food and molecular," the political figure said.

Putin's most vocal domestic critic was flown to Germany in August for treatment after falling violently ill on a flight from Siberia.

European laboratories later concluded he was poisoned with the Soviet-era nerve agent Novichok.

The popular 44-year-old anti-graft campaigner, who has tracked the wealth of Russia's elites, returned to Moscow in January only to be arrested and sentenced to a penal colony for two and a half years for allegedly violating the terms of a suspended sentence.

Both Washington and Brussels have demanded Navalny's immediate release while two United Nations human rights experts on Monday called for an international investigation into his poisoning.