BRUSSELS (AP) — NATO says Russian President Vladimir Putin is unlikely to attend the alliance's upcoming summit in Chicago due to his busy schedule at home.NATO Secretary-General Anders Fogh Rasmussen said Wednesday that he spoke to Putin, who is scheduled to be inaugurated as Russian president shortly before the May 20-21 meeting.Fogh Rasmussen said: "We have agreed that the timing is difficult."NATO and Moscow have been at odds over U.S.