FILE PHOTO: A prototype for U.S. President Donald Trump's border wall is seen through the border fence between Mexico and the United States, in Tijuana, Mexico January 7, 2019. REUTERS/Jorge Duenes/File Photo

WASHINGTON (Reuters) - The Trump administration has identified roughly $8 billion in U.S. government funds that President Donald Trump could tap to pay for work this year on his proposed U.S.-Mexico border wall under a national emergency, a top U.S. White House official said on Friday.

In addition to $1.38 billion from a bipartisan funding bill, the administration will draw on funds from other parts of the government, including the Treasury and Defense departments, White House chief of staff Mick Mulvaney told reporters.

Democrats were expected to oppose Trump’s declaration of an emergency as an unconstitutional attempt to pay for his wall without approval from Congress.