"The Sahara border can't be bigger than our border with Mexico", he reportedly said, apparently unaware of the size of the desert.
Fact is the Sahara desert is 3,000 miles long, which is approximately 1,000 miles longer than the U.S. Mexican border. Most estimates for the Sahara put it at about 3,000 miles long from east to west.
Borrell made the remarks in a speech Tuesday during a lunch at Club Siglo XXI in Madrid, in reference to the expected massive growth in the number of young Africans seeking work in the next two decades.
The Spaniard did not reveal when the commander-in-chief floated the plan, although other sources said it was in June when he flew to the States during the White House visit of Spain's King and Queen.
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It took a lot of courage for Christine Blasey Ford to come forward to share her story of sexual assault by Brett Kavanaugh . Grassley said he was disappointed that Democrats - or Ford's attorney - had not come forward with the allegations sooner.
The border issue was also a concern in the United 2026 World Cup joint bid between the US, Canada, and Mexico.
The Spanish government has not yet commented on Trump's suggestion, but, a spokesman for the foreign ministry confirmed the foreign minister's remarks about the conversation, but said, "We won't be making any further comment on the minister's remarks".
Figures released by the International Organization for Migration (IOM) earlier this year showed Spain has overtaken Italy as the most popular choice for migrants attempting to get to Europe by sea.
Many of these cross the Sahara to Morocco and on to Spain across the Mediterranean or over two high fences into the Spanish overseas territories of Ceuta and Melilla in northern Morocco.
Migrants have increasingly been looking to Spain after being shunned by Italy's populist government, which has worked to clamp down on refugees, going so far as to shut its ports to migrant rescue ships.