I read BBC news today, and this title 'Russia warned of 'consequences' if Navalny dies.' made me confused.
The news says the U.S warned Russia of 'consequences' if Navalny dies. My question is why the title does not have 'is' (Russia is warned of 'consequences' if Navalny dies.) for the passive form. Then I searched some answers online, someone explains 'Russia warned of 'consequences' is not a completed sentence. Therefore, the title does not need to use 'is' for the passive form.
If anyone can confirm this explanation, and why this sentence is not a completed sentence.