The United States on Friday announced a new $425 million military assistance package for Ukraine that features air defense and artillery munitions and anti-tank weapons to aid its fight against Russia's invasion.

That equipment, along with small arms ammunition, demolitions munitions and other items, is part of $125 million in gear drawn from US existing military stocks.

The package also includes $300 million in laser-guided munitions to counter drones, which will be funded via the Ukraine Security Assistance Initiative (USAI).

That means it will not immediately arrive on the battlefield, as the munitions need to be procured from the defense industry or partners, rather than drawn from American stockpiles.

The Pentagon said in a statement that the USAI funding was provided by a continuing resolution passed by Congress in late September to temporarily fund the government.

But it is now gone: The package "exhausts the remaining USAI funds currently available to support Ukraine," the statement said.

The Pentagon also made the case for Ukraine aid, saying it is "a smart investment in our national security."

"It helps to prevent a larger conflict in the region and deters potential aggression elsewhere, while strengthening our defense industrial base and creating highly skilled jobs for the American people," it said.

The United States is by far the biggest donor of security assistance to Ukraine, committing more than $44.2 billion since Moscow invaded Ukraine in February 2022.

But some hardline Republicans oppose continued assistance for Kyiv, putting the future of American aid for Ukraine in doubt.