Kast raised his key issue of illegal immigration by calling on the military to build barriers along the border with Bolivia and then signed three decrees on the subject.
The conservative father of nine won re-election in December, defeating communist Jeanette Jara. His victory gives U.S. President Donald Trump another ally in Latin America.
Kast is Chile's most hardline leader since the brutal military dictatorship of 1973-1990 under Augusto Pinochet - whom Kast admires and has repeatedly praised.
