In a clear message to the West and Ukraine, Russian President Vladimir Putin on Tuesday signed a decree broadening the scope of Moscow using nuclear weapons on a non-nuclear state if it is supported by nuclear powers.

This decision comes on the 1,000th day of Russia invading Ukraine, after Joe Biden gave Ukraine permission to use its long-range missiles to strike deeper in Russian territory.

The Biden administration had made a significant policy change, allowing Ukraine to use US-made ATACMS missiles to strike targets inside Russia for the first time.

This decision came just two months before President Joe Biden hands over power to Donald Trump, who has expressed scepticism about US military aid to Ukraine.

The Kremlin vowed on Tuesday to defeat Ukraine, saying Western support for Kyiv would have no impact on the conflict and that western aid "cannot affect the outcome of our operation. It continues, and will be completed."

"The military operation against Kyiv continues," Kremlin spokesman Dmitry Peskov said.

He also said that aggression by a non-nuclear state with the participation of a nuclear state is considered as a joint attack referring to Ukraine and its Western backers. 

Peskov added that, Russia "has always viewed nuclear weapons as a means of deterrence," and that they would only be deployed if Russia feels "forced" to.

NATO chief has said that Putin must not 'get his way' in Ukraine. However only a month back, he had said that he does not see an imminent danger of nuclear weapons from Russia despite "reckless and irresponsible" from the country.

The nuclear doctrine will also be extended to Russia's close ally Belarus.

This reflects Putin's swiftness to force the West to back down while Russia continues its slow moving offence in Ukraine. 

According to a Bloomberg report, Ukrainian armed forces carried out their first strike in a border region within Russian territory with a ATACMS missile, RBC Ukraine reports, citing an official in the nation's military.

The war between Russia and Ukraine, the deadliest conflict Europe has seen since the World War II, marks its 1,000th day today. Over one million people have reportedly either died or have been grievously injured since the beginning of the war.

Amid the grim reality of the deadliest war of the 21st Century, cities, towns, and villages in Ukraine have been devastated and now lie in ruin. The loss of human life and material wealth keep mounting in a never-ending series of heartbreaking stories emerging from the war-torn country.

Both Russia and Ukraine have diminishing populations and have been struggling from even before the war. The staggering death count due to the war will thereby have far-reaching demographic implications for both nations.