"Our strong alliance with Poland and NATO remains critical to deter conflict and ensuring that war between great powers never again ravages Europe and that the world will be a safer and better place," Trump said at a joint press conference with Polish President Andrzej Duda.

"America is committed to maintaining peace and security in Central and Eastern Europe," the head of state said.

"We are working with Poland in response to Russia's actions and destabilizing behaviour," he added.

In answer to the question whether the heads of state had discussed possible security guarantees for Poland by the U.S. as long as danger from the direction of Russia remained, Trump said that no guarantees were discussed.

Trump is meeting the heads of state of the Three Seas Initiative, to which 12 countries from the Mediterranean and the Black Sea to the Baltic Sea belong, among them President Kersti Kaljulaid.

U.S. to sell Patriot missile system to Poland

According to Polish defense minister Antoni Macierewicz, the White House has agreed to sell Poland the Patriot surface-to-air missile system. Macierewicz announced the decision on Thursday while Trump was on a state visit to Warsaw and meeting Polish top officials, among other things to discuss security and energy issues.

The according agreement has not been signed yet. According to the minister, Poland will invest around 30 billion zloty, or €7 billion. The purchase is another step taken by Poland to increase its defensive capability in the face of increasing Russian military activity.