Mexico has again expressed opposition to funding the construction of a wall along its border with the US.

Responding to a Sunday tweet from President Donald Trump, who made the idea of a border wall central to his 2016 presidential campaign, the Mexican foreign ministry refused to pay for the wall “under any circumstances.”

“As the government of Mexico has always maintained, our country will not pay, in any way or under any circumstances, for a wall or physical barrier built on US territory along the Mexican border,” a news release from the Mexican government said.

“This determination is not part of a Mexican negotiating strategy, but a principle of national sovereignty and dignity.”

On Sunday, President Trump emphasized Mexico would pay for the wall, suggesting the nation might “reimburse” the U.S. for costs.

With Mexico being one of the highest crime Nations in the world, we must have THE WALL. Mexico will pay for it through reimbursement/other. — Donald J. Trump (@realDonaldTrump) August 27, 2017

Mexico’s former president, Vicente Fox, has been a longtime vocal opponent to Trump’s wall.

“Well, you can use my words: We’ll never pay for that f—ing wall,” Fox told CNN earlier this month. “Why should Mexico pay for the wall? What’s the reason?”

In a January phone call between Trump and President Enrique Peña Nieto released by The Washington Post, Trump emphasized it was important for him politically that Mexico fund the wall because the nation had long taken advantage of US trade policies.

“I have been talking about it for a two year period, and the reason I say they are going to pay for the wall is because Mexico has made a fortune out of the stupidity of U.S. trade representatives. They are beating us at trade and they are beating us at the border, and they are killing us with drugs,” Trump told Nieto, according to a leaked transcript of the call.

In the past, Trump has proposed numerous options in which Mexico funds the wall, including a border adjusted value-added tax, or by using Mexico’s large trade deficit with the US as leverage.

The president also last week threatened a government shut down if Congress would not pass a bill allocating funds for a border wall.

“If we have to close down our government, we’re building that wall,” Trump said in Phoenix last Tuesday, to which supporters yelled, “Build that wall!”

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