UP hasn't existed for at least 30 years. Its successor, UPI, hasn't been relevant for at least 10.
That aside, initial reports are unreliable. That is not media bias, sensationalism or incompetence -- it's just a fact of life. If you don't know that, you have clearly never worked in a newsroom.
Try this thought experiment -- something just happened in an office down the hall. Your boss tells you to go there, find out what happened, and report back in five minutes. You walk into the room, and find some people bleeding, some tending to the bleeding, and others staring at the wall in shock.
You can't go back to the boss with nothing more than "it's f'ed up down there." So you ask what happened, and everyone starts yelling at the same time. All are wigged out. Most are confused. Their accounts conflict with each other. Many are relating what they heard from an unidentified someone else. They're all talking at the same time and your boss wants an answer NOW.
So you tell the boss, "this is what they tell me," with abundant disclaimers, because you HAVE to tell him something. Then you go back and try to sift through all the information coming in.
Breaking news is chaos and panic, a massive adrenaline rush for the reporters and sources alike. At the best of times, someone is calm enough to tamp down the rumors and make sure things are properly sourced, but that doesn't always happen. Rumors slip through.
Conspiracy theorists like to claim that some elements found in initial reports that weren't repeated later prove a cover-up. 99% of the time, they weren't repeated because they were wrong.
I cited one example, the Centennial Olympic Park bomb, from personal experience. While official information was still absent, I ran into a group of people talking. One said an electrical transformer had blown up on one of the light towers. Another said he was a lineman, and that there were no transformers on the towers. A Vietnam vet said it sounded like a land mine. One of the security guards thought it was a car backfiring.
Lucky for me, I didn't have to try to stitch that together into something coherent. I was just a techie who stepped out for a smoke, and I wasn't expected to report. I don't know what I would have told my bosses if I had to tell them something.
UP long gone? Oooops! Showing my age! So Associated Press has no competition? Another case of a monopoly. Sad.
The point I was trying to make was: all the instant reports which were, according to you, unsubstantiated, should not have been made UNTIL they had their finger on some real evidence. I don’t like the vision of a bunch of reporters running around like chickens with their heads cut off, trying to make points. I tend not to believe them in the end. And I definitely do think that if this is really an enemy attack, it will be covered up clear to China.