Former president of Mexico Vicente Fox jabbed U.S. President-elect Donald Trump on Twitter Friday, calling Trump’s planned border wall between Mexico and the U.S. a “racist monument.”

“Trump may ask whoever he wants, but still neither myself nor Mexico are going to pay for his racist monument. Another promise he can’t keep,” wrote Fox, according to TheHill.com.

Trump may ask whoever he wants, but still neither myself nor Mexico are going to pay for his racist monument.
Another promise he can't keep.

— Vicente Fox Quesada (@VicenteFoxQue) January 6, 2017

Trump is reportedly coordinating with Republican lawmakers to build the proposed border wall with U.S. tax dollars.

When word about the plan got out on Thursday, Trump angrily tweeted that the plan would really just borrow taxpayer dollars because Mexico will totally pay us back later.

The dishonest media does not report that any money spent on building the Great Wall (for sake of speed), will be paid back by Mexico later!

— Donald J. Trump (@realDonaldTrump) January 6, 2017

Former Pres. Fox has been a gadfly to the Trump campaign and transition team since the beginning of the 2016 campaign, when Trump said that immigrants from Mexico are drug-dealers, criminals and rapists.