Donald Trump’s “very poor” performance in Monday’s presidential debate should concern foreign leaders who would have to work with him in the Oval Office, former Mexican President Vicente Fox said Tuesday.

Fox has been a vocal critic of the Republican presidential nominee since earlier this year, when he made headlines for suggesting America’s Southern neighbor will never pay for Trump’s “f—king wall.” In an interview with The Washington Post, he compared the first one-on-one debate between Trump and Hillary Clinton to the Disney film “Beauty and the Beast.”