KYIV — Ukraine and the U.S. are preparing a contract for 25 Patriot air defense systems, said Ukrainian President Volodymyr Zelenskyy.

Patriots are one of the most effective defenses against Russian ballistic missiles targeting Ukraine’s energy system. However, it will take years to get them, as Kyiv will have to wait in line behind other customers, Zelenskyy said during a meeting with journalists on Sunday.

“The difficulty lies in the production queue — a line of countries that have signed relevant contracts. We will be receiving these 25 systems over the years, with different quantities each year,” Zelenskyy said, adding: “The White House can change the queue if there is political will.”

He said that some European countries could give priority to Ukraine over their own Patriot deliveries, or else send batteries they currently possess to Ukraine.

“If everyone works together and there is goodwill, the White House could assist us specifically with these American systems that are already in those European countries — so that we can receive them,” Zelenskyy said.

Each system costs about $1 billion, and Ukraine’s finances are scarce. Kyiv hopes to get cash from a €140 billion reparations loan financed by frozen Russian assets that is being considered by EU countries. However, that is still not a done deal.

“Naturally, we also need to work on other sources of financing. Currently, we have 28 bilateral security agreements with various countries. The task is to secure funds and make advance payments, and within the framework of these agreements, it can be done,” Zelenskyy added.

A third way is the Prioritized Ukraine Requirements List, a NATO initiative to have allies buy weapons from the U.S. for delivery to Ukraine. Under Donald Trump, new donations of U.S. military aid have slowed to a trickle.

“This initiative is very important because it allows us to purchase the necessary American weapons, in particular missiles for the Patriot systems and some other things, and it also helps relations with the United States in general,” Zelenskyy said.