What to know about Microsoft's controversial chatbotThe new AI tool in Microsoft's search engine repeatedly told a user it loved him and said he should leave his wife. NurPhoto via Getty Images

Microsoft search engine Bing, long overshadowed by Google but newly enhanced with artificial intelligence for some users, can suggest recipes for a multi-course meal or disentangle the nuances of existentialism.

The technology has stoked controversy, however, after reported troubling results in which it expressed a desire to release nuclear secrets, compared a user to Adolf Hitler and repeatedly told another user it loved him, among other examples.

Describing conversations with the chatbot that lasted as long as two hours, some journalists and researchers have warned that the AI could potentially persuade a user to commit harmful deeds or steer him or her toward misinformation.

Despite concerns among some users, Microsoft announced on Wednesday that it made the preview of AI-enhanced Bing available on mobile and Skype, expanding access to the product.

In a series of blog posts, Microsoft has acknowledged unexpected results and placed limits on the tool.

"We've updated the service several times in response to user feedback, and per our blog are addressing many of the concerns being raised, to include the questions about long-running conversations," a Microsoft spokesperson told ABC News.

"We have put in place a range of protections and guardrails to make the new Bing a positive and helpful experience for users," the spokesperson added. "We will continue to remain focused on learning and improving our system before we take it out of preview and open it up to the wider public.”

Here's what to know about Bing's new AI feature and the controversy it stirred: