U.S. President Donald Trump said on Thursday his Mexican counterpart, Enrique Pea Nieto, should cancel his scheduled visit to Washington if Mexico refuses to pay for a wall he has ordered constructed along the border.

His message could undo a planned summit next week during which the two leaders were expected to address a relationship frayed by the new U.S. presidents determination to build a wall along their shared border and to renegotiate the North American Free Trade Agreement.

A Mexican government minister said that cancelling the meeting would cause uncertainty.

The U.S. has a 60 billion dollar trade deficit with Mexico. It has been a one-sided deal from the beginning of NAFTA with massive numbers... of jobs and companies lost. If Mexico is unwilling to pay for the badly needed wall, then it would be better to cancel the upcoming meeting, Trump said on Twitter.

Even before Trumps tweet, Pea Nieto faced growing pressure at home to scrap the meeting over objections to the border wall.

The White House did not immediately return a request for comment.

Trump signed new executive orders, including one authorizing the planned wall, on Wednesday just as a Mexican delegation led by Foreign Minister Luis Videgaray arrived at the White House for talks.

The timing caused outrage in Mexico, with prominent politicians and many on social media seeing at as a deliberate snub to the governments efforts to engage with Trump, who has for months used Mexico as a political punching bag.

But Mexican Finance Minister Jose Antonio Meade said minutes after Trumps tweet, Well have to see what happens, under what terms, what the spaces there are for dialogue, what avenues remain open. We have to wait.

Thats correct, Meade said on Mexican radio when asked if a cancellation of the meeting would fuel uncertainty.

Mexicos peso reversed gains immediately after Trumps message on Twitter.

Videgaray, who had spoken positively about his eight-hour meetings with Trumps closest aides at the White House on Wednesday and who said on Wednesday evening that the summit was on for now, was due to meet U.S. Department of Homeland Security Secretary John Kelly on Thursday.

His colleague, Economy Minister Ildefonso Guajardo was due to meet with business leaders.