What does おり mean in this sentence?

Question

Is it from the verb 居る? If it's so, why is not it ております?

怪人による被害はこれまでにない規模の拡大を続けており、…

Answer 1

In very short: it is the humble form of いる.

To give a typical example, おる is mostly used when talking about your own actions and trying to be humble (for example when talking to a superior such as your boss at work, to a customer, etc). Find something about this topic here or check the wiki about Japanese honorific speech.

In your specific example, I believe the sentence continues with something you haven't written here. In fact, おる is in the "pre-masu" form which is often used in written language to connect to the next sentence. Refer to this answer for more details on this.

EDIT: So I made some research and I think your full sentence is in fact:

怪人による被害はこれまでにない規模の拡大を続けており、現在協会側で災害レベルを判別中との...

Is it correct?

So I think we can translate this as (until the comma): the damage due to the (less literally, left by) the mysterious person (monster? Not sure what 怪人 is depending on the context) is expanding at an unprecedented scale.