French President Emmanuel Macron warned his fellow European Union leaders on Thursday that the coronavirus outbreak risked undoing the bloc’s central pillars such as its no-border zone if they failed to show solidarity in this crisis, a diplomat said, Reuters reports.

“What’s at stake is the survival of the European project,” he told the 26 other leaders in a conference call, according to a French diplomat. “The risk we are facing is the death of Schengen,” Macron added, according to the same source.