US President Joe Biden and Ukraine's President Volodymyr Zelensky hold a joint news conference in the Indian Treaty Room of the Eisenhower Executive Office Building, next to the White House, in Washington, DC, on December 12, 2023.

WashingtonCNN — 

An aid package scheduled for Ukraine later this month will be the final one unless Congress approves additional help, the White House warned Monday.

While aid provided to Ukraine thus far has been essential in resisting Russia’s invasion of Ukraine, the country “still needs our help,” National Security Council spokesman John Kirby told reporters Monday.

He pointed toward a letter to Congress from the comptroller of the Department of Defense, Mike McCord, warning the department had fully allocated all remaining funding under the department’s replenishment authority earmarked for Ukraine.

We are still planning one more aid package to Ukraine later this month. However, when that one’s done, as the comptroller Mr. McCord made clear in his note to Congress today, we will have no more replenishment authority available to us, and we’re going to need Congress to act without delay, as we have been saying,” Kirby said.

In that letter, a copy of which was obtained by CNN, McCord wrote the department will be transferring “$1,071.117 million” to its accounts to replace its stockpiles and reimburse for “defense services” provide to Ukraine. But “once these funds are obligated, the Department will have exhausted the funding available to us for security assistance to Ukraine,” McCord wrote.