This is an example of headline English.
A newspaper headline doesn't follow the same grammatical rules as prose, because the function of a headline is to express as much information as possible with as few letters as possible. This is done by, amongst other things:
1. using shorter words (e.g. "bug" instead of "bacteria");
2. omitting short grammatical words (such as articles and even some auxiliary verbs); and
3. using short, well-known phrases (e.g. "in crisis talks" instead of "are holding a series of emergency meetings").
In your example, the headline is expressing that Iran's receiving nuclear fuel is a "blow", i.e. an unpleasant surprise, for the US. Written out in full, the sentence might be something like this:
Iran has received nuclear fuel, and this is unwelcome news to the US government.
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