U.S. Republican presidential candidate Donald Trump (R) addresses a joint press conference with Mexican President Enrique Pena Nieto (L) after their meeting in Mexico City, capital of Mexico, on Aug. 31, 2016. (Xinhua/Str) (fnc)

WASHINGTON, Jan. 26 (Xinhua) -- U.S. President Donald Trump wants a 20-percent border tax on all imports from Mexico, said White House spokesman Sean Spicer on Thursday.

Spicer said Trump wanted to use the new tax to fund the proposing wall between the United States and Mexico.

Spicer's words were hours after Mexican President Enrique Pena Nieto on Thursday canceled the work meeting with Trump scheduled for next Tuesday in Washington.

Spicer didn't release any detail about how the new tax will work.

"We're working on a tax reform bill that will reduce our trade deficits, increase American exports and will generate revenue from Mexico that will pay for the wall if we decide to go that route," said Trump at a party retreat in Philadelphia on Thursday.

Analysts said although U.S. President has the authority to impose tariffs, Trump cannot simply impose a new tax on imports from Mexico because of the North American Free Trade Agreement (NAFTA) which eliminated all tariffs among Canada, United States and Mexico.

If Trump wants to impose a border tax against Mexico, he needs to withdraw the United States from NAFTA first. After notifying the other two signatory nations for six months, the United States can impose tariffs against Mexico.

Building a wall at the U.S. southern border with Mexico to be paid by Mexico was one of Trump's key election campaign pledges. Trump signed an executive order on Wednesday to build "a large physical barrier" between the two countries.

Trump reiterated earlier Wednesday during an interview that the wall project will start as soon as possible and financed by Washington, but Mexico will "100 percent" reimburse the United States at "a later date," which has been rejected by Mexican government for several times.