Ukrainian President Volodymyr Zelenskyy and Polish Prime Minister Donald Tusk discussed strengthening Ukraine’s air defenses, winter preparations and potential diplomatic contacts during a phone call on Oct. 5, according to Ukraine’s presidential office.

Zelenskyy thanked Poland and Tusk for their continued support, saying Ukraine was receiving vital assistance as Russia continued its escalation. The Ukrainian president also briefed Tusk on preparations for possible technical-level trilateral meetings involving Ukraine, the United States and Russia.

According to Zelenskyy, Ukraine is ready to participate in such discussions, but he said the United States must complete its preparations and Russia must demonstrate its readiness. The two leaders also discussed efforts to protect Ukraine’s energy system ahead of winter.

The presidents agreed to meet in person in the near future. Zelenskyy said closer cooperation across Europe would be necessary to halt Russia’s war against Ukraine.