Homeland Security Secretary Alejandro Mayorkas took a slightly tougher tone in his latest plea with migrants, asking them to wait weeks to months before traveling to the southern border.

“Do not come,” Mayorkas said in an interview with CBS News’s This Morning on Thursday. “It is ‘do not come,’ but while we are rebuilding the system that was dismantled by the prior administration, we will make the conditions as safe as possible for the children, whom we are not expelling.”