washington president donald trump say sunday expect mexico pay wall promise build along southern border resuscitate campaign promise roil u.s. relations mexico first week presidency eventually late date get start early mexico pay form badly need border wall trump say twitter post trump return mexico demand morning simultaneously try pressure congressional democrats include fund border wall must-pass spend legislation need keep u.s. government open beyond friday spokesman mexican president office say president enrique pena nieto repeat mexico pay wall republican president demand mexico pay border wall trigger diplomatic crisis southern u.s. neighbor first week presidency pena nieto jan. 26 scrap plan trip meet trump white house float idea 20 percent tax goods mexico pay wall two leaders agree follow day talk publicly payment wall mexican government say white house say two recognize differences propose wall agree work differences out trump seek wall project cost 20 billion part effort curb illegal immigration mexico reject payment construction project question attorney general jeff sessions tell abc week sunday wall would get pay one way another expect mexican government appropriate money ways deal trade situation create revenue pay doubt sessions say trump say mexico 'eventually pay border wall