Typescript: force exclude file even if it was imported

I want to exclude a *.ts file from compilation by adding it into "exclude" property in tsconfig.json. Although if I do import that file somewhere in the code it ignores the exclusion and compiles it anyway. How to force TS to exclude this file?

../

../must_be_excluded.ts

../index.ts

Using import

//index.ts
import {some_stuff} from "./must_be_excluded"

Tsconfig settings

//tsconfig.json
{
   "compilerOptions": {...},
   "exclude": ["./must_be_excluded.ts"]
}

I see must_be_excluded.js anyway!