"The president of Mexico has been very clear: Mexico will never pay for that wall," Ildefonso Guajardo tweeted on Thursday.
President Trump told the Wall Street Journal earlier in the day that Mexico could pay for his flagship project "indirectly through NAFTA," a free trade deal that is being renegotiated in Washington, D.C.
Secretary Guajardo, who is visiting the US capital for talks, emphasized that "neither today nor at any moment during the negotiations the wall was topic of NAFTA discussions."
According to a blueprint seen by US media, Trump is seeking $18 billion over ten years for the wall project. The administration reportedly asked the US Congress to set aside funds for the construction of several hundreds of miles of barriers on the southwestern stretch of the border.