The new service searches hundreds of different news sources to answer a user's query. The exact number of sources is confidential.

Results are presented in similar fashion to a Google News search, with "related" articles about the same event grouped together. Free and charged-for articles are displayed side by side.

With pages from commercial websites, the cost of viewing them is also shown. Google says search results are based on relevance, not partnerships with companies.

Users can also view articles using a timeline that displays key dates associated with a story.

So the first Moon landing would highlight 1969 as a key date, but also identify other years when lunar landings took place or when the topic was in the news.

In a move the builds another link in the bridge between new and traditional media, Google and the Associated Press have entered into a content agreement for stories and photographs.

"The license in this agreement provides for new uses of original AP content for features and products we will introduce in the future," said Google spokesperson Sonya Boralv.

Financial terms of the deal were not disclosed.

AP had reportedly been uncomfortable with Google's practice of aggregating and displaying the news wire's content on its Web site with no payment to AP. Now, Google appears to be willing to pay for the content as part of a new product planned for Google News.

The Paris-based World Association of Newspapers, whose members include dozens of national newspaper trade bodies, said it is exploring ways to "challenge the exploitation of content by search engines without fair compensation to copyright owners."

Web sites like Google and its specialised Google News service automatically pull in headlines, photos and short excerpts of articles from thousands of news sources, linking back to the publishers' own site. Google News does not currently carry advertising.

"They're building a new medium on the backs of our industry, without paying for any of the content," Ali Rahnema, managing director of the association, told Reuters in an interview.

"The news aggregators are taking headlines, photos, sometimes the first three lines of an article -- it's for the courts to decide whether that's a copyright violation or not."