Confusing Sometimes when to change the definite article in "avoir besoin de"

Question

I understand when to use "de" as well as "de l" for vowels, however i also noticed sometimes "du" gets used which is confusing. Came across one of the posts by Tom in the comment section: j'ai besoin de soutien - I need support (general)

J'ai besoin du soutien du gouvernement - I need government support (specific)

How come this is still correct which still contains the word "support" with a different article: j'ai besoin d'un soutien financier and NOT j'ai besoin du soutien financier,

This actually confuses me the most:
j'ai besoin de soutien and NOT j'ai besoin du soutien. Last i checked, le soutien est masculin.

Accepted Answer

Hi Victor,
J'ai besoin de soutien = I need help ( we don't know who from)
J'ai besoin du soutien du gouvernement = I need government help
J'ai besoin d'un soutien financier = I need financial help
You cannot say -
J'ai besoin du soutien 
as it is an unfinished sentence , some one might ask which help are you in need of ?
I hope this clarifies matters!