President of Poland Andrzej Duda has said it is necessary to "do all we can to ensure that Crimea becomes a part of Ukraine again."

"There can be no concessions to Russia in this regard whatsoever," he said in a video address to the Third Summit of the Crimea Platform on Wednesday.

"Moscow has to return all the seized territories and face the consequences of its actions. Let us not forget that what is really at stake in this war is keeping the world order based on respect for international law, territorial integrity as well as the freedom and the right of nations to choose their own future," the Polish president said.

He also said that the summit is a proof that "the international community has understood the significance of the illegal occupation of Crimea."

"The developments of March and April 2014 were a signal for us about Russia's real intentions concerning Ukraine. The annexation of its territory annihilation of the statehood and destruction of Ukrainian culture and language. Hence, we made an appeal for international solidarity with Ukraine already then," Duda said.

"Together we will de facto begin to agree on a new international security architecture and a new global order… Therefore, the de-occupation of Crimea and restoration of Ukraine's full territorial integrity are necessary preconditions not just for the security of the Azov, Blatic Sea region but also for the stability of the global security architecture," the Polish president said.