U.S. President Donald Trump said Dec. 28 that he would close the country's entire southern border with Mexico if Congress does not approve funding for the construction of a wall, potentially worsening a dispute that has led to an already weeklong partial government shutdown.

"We will be forced to close the Southern Border entirely if the Obstructionist Democrats do not give us the money to finish the Wall & also change the ridiculous immigration laws that our Country is saddled with," Trump wrote on Twitter.

"Either we build (finish) the Wall or we close the Border," he said in another tweet.

Trump is seeking $5 billion in funding for his proposed border wall between the U.S. and Mexico, a demand that triggered the government shutdown on Dec. 22 as lawmakers failed to reach an agreement over a spending bill.

Earlier this week, Trump said the government shutdown will not end until an agreement over the wall funding is reached, Reuters reported. Incoming House Speaker Nancy Pelosi told USA Today that the Democrats do not plan to support the proposal.