A senior Mexican official said his country stands ready to work with the Biden administration when a pandemic-related public health order lifts later this month — but if, and only if, the U.S. agrees to fundamental steps, including strengthening policies for resettling migrants in the U.S. and fostering economic development in the migrants’ homelands.

In an interview with The Dallas Morning News, Roberto Velasco, a top diplomat and Mexico’s chief officer for the North America Unit at the Mexican Secretariat of Foreign Affairs, described negotiations with the U.S. as “intense” and “round-the-clock.”

The ongoing negotiations between officials from both countries come as more than 1,500 migrants made their way from Ciudad Juárez to El Paso on Sunday, after some said they escaped or were rescued by Mexican federal forces from a cell controlled by members of organized crime.