Marcin Przydacz made the statement in an interview with Polish state news agency PAP on Friday.
Earlier in the day, Russian President Putin signed documents to incorporate four regions of Ukraine into Russia at a televised ceremony in the Kremlin.
The move came after Russia held what it called referendums in occupied areas of Ukraine and declared the annexation of the Donetsk, Luhansk, Zaporizhzhia and Kherson regions.
'Poland refuses to recognise' Putin's annexation of Ukrainian territory
Commenting on Putin’s decision, the Polish deputy foreign minister said: “Poland refuses to recognise this sort of action, because it lacks any factual or legal basis, and is extremely incompatible with the norms of international law.”
Przydacz stressed that “most countries have taken a similar stance,” adding that in the present situation, it is vital that Poland “continue its current policy of support to Ukraine.”
“Ukraine is entitled to defend its sovereignty and independence,” he added.
Putin 'will be seeking to continue his aggressive policy'
Przydacz warned: “Vladimir Putin doesn’t give any consideration to the interests of smaller countries, such as Ukraine, he has much contempt for the norms of international law and the world order, and so he will be seeking to continue his aggressive policy, to stoke anxiety and sow fears of a further escalation, both in Western Europe and in the countries of the region.”
“And he’ll be looking to exploit anxiety about nuclear war,” the Polish deputy foreign minister added.
'Catastrophic consequences for Russia' if Putin uses nuclear weapons in Ukraine
According to Przydacz, Putin’s nuclear threats must be treated “responsibly and seriously,” but “they must not make us abandon our policy.”
He stressed: “If Vladimir Putin succeeds today in intimidating the Western world with his threats of using nuclear weapons, then he will soon want to dominate not only Ukraine, but also other countries, by wielding this threat of deploying weapons of mass destruction.”
Przydacz said that “the stance of allied countries and the US” was "of key importance in this matter."
He quoted the words of US National Security Advisor Jake Sullivan, who said last Sunday that “there will be catastrophic consequences for Russia” if Putin uses nuclear weapons in Ukraine, and that “the United States will respond decisively, alongside our allies and partners.”
EU leaders, OSCE condemn 'illegal annexation'
Meanwhile, the 27 European Union national leaders condemned the Kremlin’s annexation of four Ukrainian regions in a joint declaration on Friday.
They said: “We firmly reject and unequivocally condemn the illegal annexation by Russia of Ukraine's Donetsk, Luhansk, Zaporizhzhia and Kherson regions.”
European Commission President Ursula von der Leyen said in a tweet: “All territories illegally occupied by Russian invaders are Ukrainian land and will always be part of this sovereign nation.”
The Organisation for Security and Cooperation in Europe (OSCE), led by Poland’s Foreign Minister Zbigniew Rau as its current Chairman-in-Office, condemned “the Russian Federation’s illegal annexation of territory in the Donetsk, Luhansk, Zaporizhzhia and Kherson oblasts of Ukraine, as well as the continued occupation of Crimea,” the PAP news agency reported.
Friday was day 219 of the Russian invasion of Ukraine.
Source: PAP, consilium.europa.eu, osce.org, euronews.com, bbc.com