WASHINGTON (AP) — President Donald Trump is threatening to close the U.S. border with Mexico if Democrats in Congress don't agree to fund the construction of a border wall.

Trump tweeted Friday morning that "We will be forced to close the Southern Border entirely," unless a funding deal is reached with "the Obstructionist Democrats."

Trump's demand for money to build the border wall and Democrats' refusal to give him what he wants has caused a partial government shutdown that is nearly a week old. Congress adjourned for the week without a resolution in sight.

The shutdown is idling hundreds of thousands of federal workers and beginning to pinch citizens who count on some public services.