President Donald Trump said on Thursday the United States had demonstrated its commitment to NATO's defense through words and actions, and called on Russia to end its "destabilising" action in Ukraine and elsewhere in the world.
Mr Trump's reference to Article Five of the NATO treaty, which guarantees that alliance members will defend each other, represented a change of tone from the president, who upset US allies by not mentioning support for the provision during a trip to NATO headquarters in May.
His criticism of Russia comes ahead of his first face-to-face meeting with Russian President Vladimir Putin in Germany on Friday.
"We urge Russia to cease its destabilizing activities in Ukraine and elsewhere and its support for hostile regimes including Syria and Iran, and to instead join the community of responsible nations in our fight against common enemies and the defense of civilization itself," Mr Trump said in a speech in Warsaw.
At a press conference with Polish president Andrzej Duda earlier in the day, he also conceded that Russia "may have" tried to influence the 2016 election that brought him to power, but suggested others too may have been involved.
Mr Trump used the speech to paint a picture of the West facing existential challenges to "defend our civilisation" from terrorism, bureaucracy and the erosion of traditions, according to the extracts.
He pointed to Poland -- which in the last century endured Nazi and Soviet occupation -- as an example of resolve.
"The story of Poland is the story of a people who have never lost hope, who have never been broken, and who have never forgotten who they are," he said in his speech.
Mr Trump called on the West to defend its traditions.
"Americans, Poles, and the nations of Europe value individual freedom and sovereignty," he said.
"We must work together to counter forces, whether they come from inside or out, from the South or the East, that threaten over time to undermine these values and to erase the bonds of culture, faith and tradition that make us who we are."
