That could be misread too though depending on when you're reading it and when you think the article was written in relation to the events. If it's a quick article right after it reads like the original verbiage but if you think it happened a while before the article was written it sounds more authoritative that there were no injuries. The "it is unclear" phrasing makes the ambiguity clear that the author doesn't know if there were any at the time of writing.