(CNN) The Trump administration is discussing diverting more money from the Pentagon budget to constructing the border wall, a US official familiar with funding of the project told CNN.

The move comes after the administration has already moved $3.6 billion of military construction funds towards President Donald Trump's trademark project following his failed attempts to secure congressional funding. Not only will the Pentagon back the project, the Interior Department announced Wednesday that it will soon transfer 560 acres along the US-Mexico border to the Army to allow for border wall construction.

Officials are also discussing how to replenish that $3.6 billion, the source told CNN. To help fund the project, the administration wants $5 billion for Customs and Border Protection in the Homeland Security budget -- for the wall, but also for processing centers.

The Washington Post reported on Thursday the administration could divert $18.4 billion more in funding for nearly 500 miles of new barrier by the 2020 election. The paper cited planning documents indicating that the government would need to either buy or claim by eminent domain almost 200 miles of land for the project.

As Trump has been pressuring aides for progress on the wall, his administration has been plotting a strategy for funding it through the next fiscal year, according to US officials familiar with the situation.

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