NATO leaders reaffirmed their commitment to the alliance's open door policy in accordance with Article 10 of the Washington Treaty.

"The first step is the deployment of four new NATO battlegroups. In Bulgaria, Hungary, Romania, and Slovakia. Along with our existing forces in the Baltic countries and Poland, this means that we will have eight multinational NATO battlegroups all along the eastern flank. From the Baltic to the Black Sea," said NATO boss Jens Stoltenberg said.

"We face a new reality for our security. So we must reset our deterrence and defense for the longer-term," he stressed, adding that "there is a new sense of urgency. Because we cannot take peace for granted."