Former Mexican president Vicente Fox has taken another sharp jab at President Trump on Twitter, questioning why the American president needs a vacation and urging Trump to "just leave" if he isn't happy with his job.

"Donald Trump leaving on vacation, huh? What for?" Fox tweeted. "If you're not happy with your job, just leave. After all, it was never for you."

Fox has been an outspoken critic of Trump, who left Friday on a 17-day vacation at his secluded golf club in Bedminster, N.J. Fox was president of Mexico for six years while George W. Bush was the U.S. president.

Fox's tweet slamming Trump about his vacation came on Friday, just one day after Fox tweeted to Trump that "once again I tell you: we're not paying for the f***ing wall."

"Don't try (to) use us for your own good," Fox tweeted Thursday.

Fox is a fierce opponent of the border wall that Trump has promised to build to keep out undocumented immigrants. Trump said during his presidential campaign that he would get Mexico to pay for the wall.

However, Mexico's current president, Enrique Peña Nieto, has repeatedly told Trump that Mexico will not fund the U.S.-Mexico barrier despite demands from Trump. Instead, Trump has turned to Congress for money to begin building the wall.

The House recently passed a spending bill that included $1.6 billion to fund construction of the wall along about 70 miles of the 2,000-mile border. The bill is not expected to pass the Senate, where Democrats have the power to block funding.

On Monday, Fox tweaked Trump with a tweet referring to the Trump White House as a "really bad reality TV show." Trump, of course, is the former host of "The Apprentice" and "The Celebrity Apprentice" reality TV shows on NBC.

"I can't change the channel," Fox tweeted. "Sad!"

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