Ukrainian President Volodymyr Zelensky sent a letter to U.S. President Donald Trump warning about Ukraine's worsening shortage of air defense systems, particularly anti-ballistic missile capabilities.

Axar.az reports, citing Kyiv Independent, Zelensky instructed Air Force Commander Mykola Oleshchuk on April 16 to urgently contact partner countries that had pledged Patriot missiles and other air defense supplies as Ukraine's stockpile of interceptors continued to decline.

The directive followed Zelensky's warning that supplies of U.S.-made Patriot missiles had reached a critical level.

"I, on behalf of the Ukrainian people, respectfully ask the president and the U.S. Congress to remain engaged," the letter says. "And to help us secure this vital tool of protection against Russian terror — Patriot missiles PAC-3 and additional systems — to stop Russian ballistic missiles and other Russian missile attacks."