The subject of the verb
"Strike kills 20" obscures the actor. "Country X strikes country Y, killing 20" names them. "Country Y suffers strike, 20 dead" rotates the subject. The same event, three different framings, three different inferred blame patterns.
Passive voice
"Twenty killed in strike" is passive. It avoids naming the actor. Persistent passive voice across a body of coverage is a strong framing signal.
Modifier discipline
"Alleged", "reported", "confirmed" do different work. An outlet that uses "alleged" for one side's claims and "confirmed" for the other side's — without a difference in evidence — is making an editorial choice, not a factual one.