Speaking on a panel discussion with Mexico President Enrique Pena Nieto, Merkel argued that building border walls disregards the root of immigration issues.
“Obviously the main reason for people leaving must be addressed on site first, which means putting up walls and cutting oneself off will not solve the problem,” Merkel said, as translated by Reuters. Improving standards of living and employment opportunities everywhere should be prioritized, she said.
Her comments take aim at Trump’s election pledge to make Mexico pay for a “big, fat, beautiful wall” along the U.S.-Mexico border to keep immigrants from crossing into the U.S.
A long record exists of such walls failing and friendly diplomacy succeeding, said Merkel, whose government has welcomed more than a million refugees into Germany since 2015.
“It’s an issue you can study well in the history of China with the (Great) Wall of China, you can study it in the history of the Roman Empire,” she said during the panel. “Essentially, only when great empires have managed to forge sensible relationships with their neighbors and to manage migration has it been a success.”
This article originally appeared on HuffPost.