File Photo: Members of a migrant caravan from Central America and their supporters look through the U.S.-Mexico border wall at Border Field State Park before making an asylum request, in San Diego, California, U.S. April 29, 2018. (Xinhua/REUTERS)

WASHINGTON, Dec. 28 (Xinhua) -- U.S. President Donald Trump on Friday threatened to close the southern border amid an ongoing partial government shutdown, resuming his push for the funding of a long-promised U.S.-Mexico border wall.

"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 tweeted Friday morning.

"We build a Wall or close the Southern Border," the president said, accusing Mexico, Honduras, Guatemala and El Salvador of "taking advantage" of his country for years.

"No end in sight to the President's government shutdown," Democratic Senator Dick Durbin of Illinois tweeted Thursday. "He's taken our government hostage over his outrageous demand for a $5 billion border wall that would be both wasteful and ineffective."

Drew Hammill, a spokesman for Democratic House Leader Nancy Pelosi, tweeted Thursday, "Democrats have offered Republicans three options to re-open government that all include funding for strong, sensible, and effective border security", but not the president's wall.

The U.S. Senate convened briefly Thursday afternoon before adjourning until next week, with no signs of a deal to end the budget impasse that has shut down a quarter of the federal government.

The upper chamber will reconvene on Monday, Dec. 31, for a pro forma session only, and then return to the Capitol Hill to renew budget deliberations on Wednesday, Jan. 2, a day before Democrats are set to take control of the House.

"With the House Majority, Democrats will act swiftly to end the Trump Shutdown," Hammill said.

Trump's approval rating dropped slightly to 44 percent in December amid the shutdown, a two-point fall from last month, according to a Harvard CAPS/Harris Poll survey, The Hill reported Friday.

The shutdown, currently in its seventh day, has affected nine federal agencies, forcing about 420,000 federal employees, who are deemed essential, to work without pay, while 380,000 others have been given unpaid leave.