"You will get what you need," he told a reporter for a Texas newspaper.
Mr. Trump also took time at the same news conference to defend his pardon of ex-Arizona Sheriff Joe Arpaio, saying it was the right decision.
"I stand by my pardon of Sheriff Joe, and I think the people of Arizona who really know him best would agree with me," the President added, explaining that he released the news while the nation was paying close attention to Hurricane Harvey's trek to the Texas Gulf Coast.
"In the middle of a hurricane - even though it was a Friday evening - I assumed the ratings would be far higher than they would be normally," Mr. Trump said.
Mr. Trump will go to Texas on Tuesday to check on damage from Harvey. He told reporters he will make another visit on Saturday.