Hmmm - "at least they are not armed" was my incorrect answer and I try to understand the difference from "they are not even armed" ---- can you help??
"ni siquiera" is a fixed expression, meaning "not even'.
ni siquiera tienen zapatos = they don't even have shoes.
In my dictionary the "ni" makes it "not even" Without the "ni" it would be "They at least are are armed."
What would be "At least they are not armed", then?
at least = al menos
"al menos no están armados"
Same idea, it would be: "Por lo menos, no están armadas."