BEIJING, Sept. 25 (Xinhuanet) -- Facebook was subpoenaed Monday by New York State Attorney General Andrew Cuomo who accuses the social networking site of failing to keep young users safe from sexual predators and not responding to user complaints.

Cuomo said in a letter sent with the subpoena for documents that a preliminary review found defects in Facebook's safety controls and in its response to complaints. He said the shortcomings contrasted with assurances made by the company.

In recent weeks, N.Y. state investigators went undercover to test Facebook's safety controls and procedures, posing as underage users. The investigators were solicited by adult sexual predators and could access pornographic images and videos, Cuomo said.

A spokeswoman for Facebook, based in Palo Alto, California, said the company was aware of the subpoena and was preparing a statement.

Cuomo's subpoena came during a joint 50-state investigation into Facebook, News Corp's MySpace website and other online social networks. Such sites have come under scrutiny because of concerns they may fall short in protecting young users.

Connecticut Attorney General Richard Blumenthal, North Carolina's Roy Cooper and Ohio's Marc Dann said they met with Facebook last week.

"We are negotiating with Facebook ─ including a productive, face-to-face meeting with Facebook representatives last week in my Hartford office," Blumenthal said. "Facebook has a long way to go before we are satisfied."

Separately on Monday, the Wall Street Journal reported that Microsoft Corp was in talks to buy a minority stake in Facebook that could value the company at 10 billion U.S. dollars or more in total.

Citing sources familiar with the matter, the Journal said Microsoft sought to buy up to 5 percent of Facebook for 300 million dollars to 500 million dollars.

(Agencies)