Estonian Prime Minister Kaja Kallas has called on the West to stand united and persevere amid intense diplomatic efforts to prevent war in eastern Europe.
"Our unity in Europe is of key importance at the moment. We must have strategic patience," she said ahead of a trip to Germany.
"The unity has held up so far and we are all working together to stay strong and united against Russian aggression – aggression that does not only affect Ukraine but Europe in general."
Russia has massed tens of thousands of troops close to Ukraine's borders, triggering fears that Moscow may be planning to invade. While the Kremlin has denied any such intention, western leaders have been holding talks to try and avert conflict.
"Our diplomacy will have a chance only if beefed up with credible deterrence and force posture," Kallas said.
She is expected in Berlin on Thursday, together with Latvian Prime Minister Krisjanis Karins and Lithuanian President Gitanas Nauseda. Their talks with German Chancellor Olaf Scholz are due to focus on the Ukraine crisis and the security situation in Eastern Europe.
"We must keep in mind that neither NATO nor the European Union has caused this crisis," Kallas added. She said NATO was not planning to attack anyone and is a defensive alliance. "So it is Russia who must de-escalate."
Kallas spoke out against making any concessions, saying European security architecture had to be upheld and de-escalation could not come at gunpoint and at the expense of Ukraine.
"Anything seeing as an appeasement by Russia would send an encouraging signal to Russia and could lead to similar or even bolder strong-arm pressure elsewhere."
Some observers say Moscow may be seeking concessions from NATO, as the build up of troops came as the Kremlin demanded that NATO halt its eastward expansion and pledge to never admit Ukraine.