President Donald Trump has proposed a 25 percent cut to the signature military fund designed to offset Russian aggression in Eastern Europe, according to the Defense Department's budget documents unveiled Monday.

Budget proposals for fiscal 2021 released Monday afternoon call for $4.5 billion for the European Deterrence Initiative, a fund started by the Obama administration in the aftermath of Russia's 2014 invasion of parts of eastern Ukraine and annexation of the Crimean Peninsula, which sparked a conflict that continues to inflict casualties on both sides. The latest proposal represents a precipitous drop from the $6 billion enacted for the current fiscal year and $6.5 billion the year before. Congress approved funding in line with administration requests for those years.

Trump has repeatedly expressed criticism of U.S. programs like the EDI that provide training, resources and money for foreign governments throughout Europe, calling on other U.S. partners to do more. The president has previously raided this fund as a workaround to pay for a wall along the southern U.S. border after Congress refused to allocate those funds. Defense Secretary Mark Esper is expected to make an announcement later this week on how the military will pay for additional border wall construction, CNN reports, after Defense budget officials on Monday said that decision was not yet final.

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The proposal released Monday does not represent precisely how the Pentagon will in fact spend money for the coming year as Congress will make significant changes in its appropriations process. Support for countries facing Russian aggression, including Ukraine, has traditionally enjoyed rare bipartisan support on Capitol Hill, though that backing has begun to crack amid the president's outspoken skepticism of such programs. Trump has continued to claim that Ukraine attempted to influence the 2016 election.

The line item shrinking funds for European support is contained within a subsection of the overall budget known as Overseas Contingency Operations or OCO, a flexible account that many critics consider a de facto slush fund for the Pentagon. All other funds within that proposed budget were slashed for the coming year, including support for local Afghan security forces, for Iraqi and Syrian forces fighting the Islamic State group and other international security partnerships.

Trump unilaterally withheld a portion of the fund specifically designed for support to Ukraine last summer at the same time as a telephone conversation in which he asked Ukrainian President Volodymyr Zelenskiy to investigate a political rival. The circumstances, which were subject to multiple whistleblower complaints, spurred outrage from Congress that prompted impeachment proceedings.

That amount for the Ukraine Security Assistance Initiative last year, $250 million, will again be included in the Pentagon budget released Monday, though top White House officials including national security adviser Robert O'Brien have repeatedly said the president remains skeptical of similar foreign assistance.