U.S. President Donald Trump said Tuesday the ongoing partial government shutdown won't end until a border wall is approved, demonstrating his unwillingness to budge on the issue.

"I can't tell you when the government is going to reopen... (Not until) we have a wall, a fence, whatever they'd like to call it," Trump told reporters in the Oval Office, noting that "much of it is 30 feet high."

"It's a barrier from people pouring into our country... It's a barrier from drugs. There is a problem in this world today called human trafficking... We are not going to let that take place," the president said. "We can't do it without a barrier, we can't do it without a wall."

The partial government shutdown, which began midnight Friday, was triggered by the White House and Congress' failed attempts to resolve a budget impasse over the funding of the president's promised U.S.-Mexico border wall.

Senate Democratic leader Chuck Schumer said Saturday that a physical barrier is off the option. "What we do support -- Democrats and Republicans -- is real, effective border security. But not a wall. The wall is President Trump's bone to the hard right."

"Democrats have always been for smart and effective ways to secure our border," Schumer said. "We are pushing for technology, like drones and sensors, and inspection equipment."

Trump has long demanded 5 billion U.S. dollars for the border wall, a centerpiece of his 2016 campaign, but Democrats were only willing to approve a funding of 1.3 billion dollars to enhance border security.

White House Office of Management and Budget Director Mick Mulvaney told "Fox News Sunday" that the White House has given a "counter-offer" that was "between those two numbers."

Schumer on Monday denounced the White House for sending mixed messages. "Different people from the same White House are saying different things about what the President would accept or not accept to end his #TrumpShutdown, making it impossible to know where they stand at any given moment," Schumer tweeted.

The U.S. Senate will return on Thursday and consider business if a deal is reached on government funding. Mulvaney said on Sunday the ongoing partial government shutdown would likely extend into the new year.