If you license full feeds from the big news agencies, like Reuters [about.reuters.com] or the Associated Press [apdigitalnews.com] then they will provide you the data that will not require a link back to the original content. Be aware that those sorts of feeds are very expensive.
Without full feeds you would have to link back to the original content.
Linking is part of the fundamental nature of the web (it's what makes the web a web). So how does it hurt you to provide a link to the web site that has paid a writer and editor to produce the news? You're probably concerned about users leaving your site to read the full article -- but they will anyway, even if you don't provide a link.