Uranium from Congo in Iran

In one of discussions in MEY, a guy who’s famous for west opposition wrote a comment and to support his comment he suggested this article Keeping "Peacekeepers" Out of Darfur. While I was reading the article I came to:

Weapons and minerals continue to flow across Congo's borders routinely, and recent news reports claim that uranium from Congo has appeared in Iran. War in
Congo continues.

It's serious issue. How and through whom uranium from Congo reached to Islamic Republic of Iran (IRI)? Who’s responsible here? We should prevent IRI to get uranium, at any price, Period.