NATO Secretary-General Mark Rutte warned on Wednesday that any attack on Poland or another ally would be met with a devastating response.
During his visit to Warsaw, Rutte emphasised that Russia is the main and most serious threat to the NATO alliance.
He noted that Moscow is transforming its economy into a war economy, which will significantly impact its ability to expand its armed forces.
Rutte expressed partial satisfaction with defence investments by Europe and Canada but agreed with President Trump that more needs to be done.
"In these uncertain times, the transatlantic partnership is the cornerstone of our alliance," Rutte added.
Polish Prime Minister Donald Tusk stated that NATO members, particularly Poland, must be prepared for all scenarios given the current discussions and negotiations where their influence is limited.