The Biden administration will deliver new air defense systems to Ukraine by delaying shipments to other U.S. allies, according to multiple reports on Thursday.

The White House said Thursday that it is rushing to send Ukraine hundreds of missiles for Patriot and NASAMS systems amid the country’s ongoing war with Russia. This will require the Biden administration to delay the shipment of such systems to other allies and partners across the globe, a move that the White House described as “difficult but necessary,” The Washington Post reported.

“We have, of course, informed all the affected countries that we are taking this extraordinary step, and we’re making every effort to minimize any negative impact,” White House National Security Council Spokesman John Kirby told reporters, according to the Post.

“The broader message here to Russia is clear. If you think you’re going to be able to outlast Ukraine, and if you think you’re going to be able to outlast those of us who are supporting Ukraine, you’re just flat-out wrong,” Kirby said, according to The Wall Street Journal.

It wasn’t clear from Kirby’s comments how long U.S. allies would be kept waiting, according to the Post. The countries that would be affected by the delay also weren’t specified, but Kirby told reporters that it would not affect Israel or Taiwan.

The Patriot and NASAMS, surface-to-air systems, have played a key role in providing Ukraine with defenses against Russian drone and missile attacks. Delivering missiles for the system to Ukraine will take top priority over the next 16 months, a senior U.S. official told the WSJ.

In addition to the missiles, Kyiv has also been seeking more batteries for the system, the WSJ reported. Ukraine currently has at least four Patriot systems, provided by the U.S. and Germany, according to the Financial Times.

“Can we get seven?” Ukrainian President Volodymyr Zelenskyy told The New York Times in an interview in May, regarding the Patriot.

The White House’s announcement on Thursday reflects Ukraine’s urgent need for military support in its war against Russia. Ukraine’s domestic weapons production is not on par with that of the West or Russia, and Kyiv has relied on the West to provide the necessary armaments to stave off Russian forces.

The U.S. alone has provided Ukraine with $175 billion in total aid, roughly $70 billion of which is solely military assistance, according to The Council on Foreign Relations.

Even with Western aid, Ukraine has struggled to hold its ground against Russian forces in the eastern theater of the war. Russian forces have seized key locations in Eastern Ukraine, exhausting Ukrainian forces and forcing them to withdraw further west.

Featured Image Credit: Official White House Photo by Adam Schultz