A racist image of Michelle Obama on the Google image search: Google has apologised over the racially offensive image

The doctored picture appears at the top of the list under a Google Image search for Mrs Obama.

Google placed a text ad above the image titled "Offensive Search Results", which states: "Sometimes our search results can be offensive. We agree."

But it refused to take the image down from its search results.

The White House has declined to comment about the picture.

Users who click on the text advertisement above the offensive image are directed to a statement from Google which explains that its results "can include disturbing content, even from innocuous queries".

"We apologize if you've had an upsetting experience using Google," the company says.

But the search engine says it does not remove images simply because it receives complaints.

"Google views the integrity of our search results as an extremely important priority," it says.

"Accordingly, we do not remove a page from our search results simply because its content is unpopular or because we receive complaints concerning it."

However, the California-based web giant says it will take down certain images, if required by law to do so.

A spokesman for Google, Scott Rubin, would not give details on how the image ended up as the top result for Mrs Obama.