NATO chief Mark Rutte warned in Warsaw that the Western defence alliance would respond with a "devastating" strike to any attack by Russia on Poland or another ally.

Poland and the nearby Baltic states - all NATO members - have increased spending on defence and training since Russian troops invaded Ukraine in 2022, expressing fears Moscow could target them.

Under NATO's Article Five, an attack against one member is considered an attack against all.

"If anyone thinks they can get away with an attack on Poland or any other ally, they will be met with the full force of this ferocious alliance," Rutte said during a visit to the Polish capital, as quoted by AFP.

"Our reaction will be devastating. This should be very clear to (Russian President) Vladimir Vladimirovich Putin and anyone else who wants to attack us," he said alongside Polish Prime Minister Donald Tusk.

Rutte's visit comes at a time when the United States is pushing for a swift end to the war in Ukraine - a negotiation in which European partners are being sidelined.

"Let's be honest, our influence on these negotiations is limited to say the least," Tusk said.

"So as NATO, as Poland, we have to be even more prepared for scenarios that we have not fully foreseen," he added.

"When the geopolitical situation changes before our eyes, the confirmation that NATO is obliged to defend Poland in any critical situation is very important for us," Tusk concluded. I BGNES