The Ukrainian leader arrived in Warsaw in the morning, just hours after Russian missiles struck multiple cities across Ukraine, killing dozens and damaging a children’s hospital in Kyiv.

Poland is the latest country to sign an agreement on security with Ukraine, following in the footsteps of the likes of the United States and the U.K.

At a joint press conference, Zelenskyy said that the agreement incorporates provisions on “cooperation in shooting down and countering air attacks” from Russia heading towards Poland.

“We have agreed to form and train a Ukrainian legion on Polish territory; it will be a new formation made up of volunteers,” Zelenskyy continued.

He also thanked Poland for all the fighter aircraft it had sent to Ukraine, adding that talks are ongoing about providing Kyiv with more planes. Tusk spoke about the immense help Polish citizens had provided to Ukraine, and how this aid will continue to flow for as long as Ukraine needs it. “You can continue to count on us,” he said.

He added that the Western world is aware that if Ukraine loses, it would end badly for Poland, Europe, and the entire Western world.

“We both believe in victory, we both believe in peace after victory, we both believe in the quick and effective reconstruction of Ukraine, which Poland will be a part of,” Tusk said.

Zelenskyy said that “44 packages of military equipment, weapons, ammunition” had already been given by Poland, and that Warsaw would send several similar packages of military aid to Kyiv by the end of this year.