I think they are after every server in US so they can sort out later which one will be useful.
Last Tuesday, our hosting provider had to reconfigure our semi-dedicated server because someone from China IP hacked into it. Yesterday, I watched our dedicated server being attacked for three hours straight. All attempts, repeated every 8-12 minutes, were made from single IP in China. Finally, I got tired of it and blocked IP.
I am seriously thinking about blocking China altogether. I hear lots of other people do it now in US.