Google’s simmering hassle with Bing appears to be erupting into a full-blown war as Google says it has caught Bing copying its search results to improve its own operation, Search Engine Land reports.

Bing doesn’t deny the accusation, according to the report. Bing is allegedly watching Google searches and using information on which sites users select from their Google search results to improve Bing’s search listings.

“Google likens it to the digital equivalent of Bing leaning over during an exam and copying off of Google’s test,” the story reports.

Google’s Amit Singhal, who oversees the search engine’s ranking algorithm, said: “I’ve spent my career in pursuit of a good search engine. I’ve got no problem with a competitor developing an innovative algorithm. But copying is not innovation, in my book.”

Rather than deny the claim, Stefan Weitz, who directs Microsoft’s Bing search engine, sent an e-mail to Search Engine Land’s Danny Sullivan that seems to confirm it:

“As you might imagine, we use multiple signals and approaches when we think about ranking, but like the rest of the players in this industry, we’re not going to go deep and detailed in how we do it. Clearly, the overarching goal is to do a better job determining the intent of the search, so we can guess at the best and most relevant answer to a given query.”