President Donald Trump wants to pay for his proposed southern border wall by slapping a 20 percent tax on imports from Mexico.

White House spokesman Sean Spicer says Trump has discussed the idea with congressional leaders and wants to include the measure in a comprehensive tax reform package.

Spicer spoke to reporters on Air Force One as Trump flew back from a Republican retreat in Philadelphia. He says that taxing imports from Mexico would generate $10 billion a year and "easily pay for the wall."

Spicer says discussions are continuing with lawmakers to make sure the plan is "done right." But he says it "clearly provides funding" for the wall.