While in Poland, NATO leaders met with Polish President Andrzej Duda, defence leaders and troops serving at Lask Airbase.

"We welcome the leading role of Poland. You are opening your borders to the hundreds of thousands of refugees fleeing the conflict, and I thank Poland for its support and strength at this dangerous time for Europe," Secretary General Stoltenberg said during a joint press event with Polish President Andrzej Duda.

You are protecting the sovereignty of our NATO Nations and our territories and we're in the business of generating peace

In Estonia, NATO leaders met with political, defence officials to discuss security challenges and delivered speeches to the troops from the multinational battlegroup in Tapa.

"We thank you for what you are doing today," said General Wolters. "You are protecting the sovereignty of our NATO Nations and our territories and we're in the business of generating peace."

NATO has layers of advanced capabilities operating throughout the land, sea, air, space and cyber domains. The Alliance is postured to deter any threat and defend Allies in all domains, across the entire Euro-Atlantic area.

"We prove to the world what solidarity really means. What it means to be in a band of brothers and sisters. Allied troops form part of a band of 3.2 million brothers and sisters. Men and women in uniform, who are willing to put it all on the line to protect and defend the freedom of almost 1 billion citizens," said Admiral Bauer.