Radoslaw Sikorski was speaking outside Paris after attending a meeting on Monday of the Weimar Triangle - a diplomatic format grouping Poland, France and Germany, initiated in 1991.
He told a press conference after the talks that they had been held at a dramatic time for Europe.
"Again we have war in Europe, again we have a dictator who grants himself the right to decide who can be a nation and who cannot, whether or not it is allowed to change borders in Europe through force," Sikorski said.
The Polish foreign minister went on to say that Putin was trying to defeat Ukraine with lies and demagogy.
"It cannot be permitted for Putin to win this war," he said. "We must fulfil our obligations towards Ukraine, both from the Budapest (Memorandum - PAP) and the recent ones on ammunition, on financial support - this is already happening - so that Ukraine can in the future become a democratic European country undergoing reform."
The Budapest Memorandum on Security Assurances, signed at an OSCE (Organisation for Security and Cooperation in Europe) conference in the Hungarian capital in 1994, provides security guarantees for Belarus, Kazakhstan and Ukraine in return for joining the Treaty on the Non-Proliferation of Nuclear Weapons.
The memorandum was signed by Russia, the United States and the United Kingdom.
Sikorski went on to express Warsaw's support for a common European defence strategy.
"Poland supports a defence union, just as once - before others - it supported an energy union," he said. "European defence in strategic harmony with Nato and the United States is an idea whose time has come."
Commenting on statements former US president, Donald Trump, made on Saturday that the US would not defend Nato countries that do not meet the alliance's defence spending guidelines, Sikorski pointed out that Poland spends more than 3 percent of its GDP on defence and would therefore qualify for protection under a Trump administration.
The foreign minister also said that if Trump had made those comments to him he would reply that an alliance is not a contract with a security firm.
"Article 5 of the Washington Treaty (providing for collective defence of Nato members - PAP) was first used after the attack on the USA on September 11, 2001.
"And then Poland sent a brigade to Afghanistan for a decade and we didn't send Washington an invoice for that," he said, adding that Nato also strengthened the US. (PAP)
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