(I'm sorry if it is a duplicate, I tried to search unsuccessfully)
I don't have the impression it generally appears in NHK news article...?
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It's a ダッシュ. It also works like an English em-dash, but here it's adding an "emotion" to the sentence. It makes the sentence look somewhat like a monologue. Its purpose here is the same as Japanese 三点リーダー (
…) or English ellipses.
The way I take it is that it represents a reflective pause -- showing the author to be lingering on the thought of the situation they have just described -- not just reporting a bit of information matter-of-factly -- while also inviting the reader to take a few moments to let the idea sink in and/or to form an image in their mind.