Donald Trump has yet to determine how Mexico will pay for a massive wall at the border that he has promised to build, a senior aide said.
White House chief of staff Reince Priebus said that a "buffet of options" remains.
He said the options include a tax on goods coming across the border, import and export taxes and even a tax on drug cartels or fines to people who come to the US illegally.
Mexican president Enrique Pena Nieto last week cancelled a meeting with Mr Trump amid tensions over his plan to build a wall at Mexico's expense.
Mr Priebus said it is early in the planning process but the broader point is that Mr Trump is fulfilling a campaign promise to build the wall.