President Trump reassured his Republican base that his border wall is necessary although the number of illegal immigrants caught at the border has plunged in recent months.

"Now, we've been so successful that the Democrats are saying, well you don't need a wall anymore because look at the good job Trump is doing. And I understand what they're saying. Except for one thing, to stop drugs, to stop human trafficking which is the new, big," Trump told the "Fox News Specialists" in an interview set to air Tuesday evening.

"Human trafficking is a tremendous problem, but to stop all of these things including illegals from coming into the country ... We need it for the drugs. We need it for the human trafficking," Trump said.

Trump approved House Republicans' decision last week to pull border wall funding from the spending bill covering the rest of the government's fiscal year, which caused some to believe he was not serious about his immigration promise.

"The wall is going to get built, but we have had such success. General Kelly has been unbelievable and now we've stopped 73 percent — the highest in the history since they've been recording this stuff," Trump said. "And now it's even better because people aren't even trying to come up. So we're saving a lot of lives because migration was dangerous and horrible, horrible for women."