The next time you see someone quoted in a news report that also contains things conveyed by an "unnamed official," pay closer attention: there is an even chance that both things were said by the same person. This is especially true if the two statements occur side by side (example: the Defence Minister said "we strongly condemn such behaviour," while a highly placed official in the ministry said that "the mindset of people doing such things is understandable.") This technique is used by people who do not want to get something attributed to them, but would like to see this information publicised without getting into trouble themselves.

While this is a good thing in general, allowing the public to know more than would be the case if journalists reported only what named sources said, there is also the danger that unscrupulous people will use this to spread disinformation (it doesn't help that journalists have to protect their sources, either).