President Trump Says He'll Shoot Immigrants at Border if They Throw Rocks

President Trump just drew the line in the sand ... if the immigrants who are marching to the U.S. border throw rocks at our troops they will be shot.

Trump said throwing rocks is like shooting firearms. He noted some of the immigrants in the caravan threw rocks at Mexican troops at the Mexican border, and it hurt some of the troops.

Trump says he hopes our troops won't have to shoot, but he made it clear ... if they throw rocks -- to him, that's a deadly weapon and our soldiers can react with firepower.

The marchers are around 900 miles from the U.S. border.