Absolutely any source of info, that is not affected by government of country involved in conflict. It can be a 3d party recorder(from another country), who accidentally recorded this event, or even a random citizen of country in which it happened. Even an unredacted video from a street camera or video registrator from a car parked near would be acceptable. I understand that sometimes there exist only 1 source of any info available, but it doesn’t mean that this source will be by default trustworthy. If there no other sources available, then simply state so. You can’t believe absolutely everything in social and information networks nowadays without confirmation.
Absolutely any source of info, that is not affected by government of country involved in conflict. It can be a 3d party recorder(from another country), who accidentally recorded this event, or even a random citizen of country in which it happened. Even an unredacted video from a street camera or video registrator from a car parked near would be acceptable. I understand that sometimes there exist only 1 source of any info available, but it doesn’t mean that this source will be by default trustworthy. If there no other sources available, then simply state so. You can’t believe absolutely everything in social and information networks nowadays without confirmation.