Donald Trump and Mexican President Enrique Pena Nieto arrive for a press conference at the Los Pinos residence in Mexico City. Reuters/Henry Romero Sean Spicer, the White House press secretary for President Donald Trump, told reporters on Thursday that the administration is pushing for a 20% border tax on Mexican imports.

"When you look at the plan that's taking shape now, using comprehensive tax reform as a means to tax imports from countries that we have a trade deficit from, like Mexico," Spicer said, according to a White House pool report.

Spicer said the border tax would be part of a broader tax reform package and would help pay for the proposed wall along the US-Mexico border, according to the report.

"It clearly provides the funding and does so in a way that the American taxpayer is wholly respected," Spicer said.

Spicer also claimed that the move "gets us in line, frankly, with the policies" of every other "major country" in the world.

Spicer later told NBC News correspondent Peter Alexander that the border tax was not a policy proposal, but an example of how to pay for the wall. Trump Chief of Staff Reince Priebus also said the tax was one of a "buffet of options" for paying for the wall.

Speaking to reporters later, Spicer said that the border tax was not ready to be rolled out "at this time" and that the tax could be directed at specific industries as well.

Spicer also said Trump wants to eventually extend the 20% import tax to all countries, not just Mexico.

"Right now we are focused on Mexico, but I think as we look comprehensively at our trade situation and countries that we have a deficit for, this is something the president has been talking about holistically. He has talked about a border tax," said Spicer.

Over 80% of Mexican exports went to the US in 2015, and the US imported $295 billion worth of goods from Mexico, accounting for 13.2% of all US imports.

While the tax would significantly increase the cost of Mexican imports, Spicer said that the US would ultimately save money because the wall would decrease the amount spent to curtail illegal immigration.

The announcement comes on the same day that Mexican President Enrique Pena Nieto canceled a trip to the US because of Trump's wall proposal.

Trump has long said that Mexico would pay to build the wall, which Republicans have estimated would cost between $12 billion and $15 billion. Nieto has said Mexico would not pay for the wall.

While Spicer did not specify the mechanisms of the border tax, based on his description, it appears the plan may be a border-adjusted tax favored by the GOP, not a straight tariff. A border-adjusted tax, the GOP argues, would not negatively affect consumers, but the full scope of its impact is unclear.

Trump previously said he was against such a tax because it was "too complicated."

Spicer said that the administration had been in contact with Congress about the tax, and it is supported by the party leadership.