A visiting starship is orbiting around your planet. An examination of their starship notes that it is heavily armed and quite capable of not only wiping out all life on your planet but probably capable of extinguishing your sun itself.
Resistance is futile.
The landing party wear nearly identical uniforms and obey the orders implicitly of their commanding officers and are heavily armed. Those little weapons appearance that they wear beguiles their sheer destructive power. They are obviously a dangerous species. You greet them under whatever circumstances they say when the occupants materialise on the planet. Their idea of peace seems the opposite of how they present themselves.