Facebook and Microsoft announced on Monday that the social network will pay 550 million U. S. dollars in cash to buy a portion of the patent portfolio the software giant recently acquired from AOL.

According to the two company's joint press release, Facebook will obtain ownership of some 650 AOL patents and patent applications out of 925 that Microsoft has agreed to purchase, plus a license to the remaining 275 AOL patents Microsoft will purchase and own.

"Today's agreement with Microsoft represents an important acquisition for Facebook," said Ted Ullyot, Facebook's general counsel. "This is another significant step in our ongoing process of building an intellectual property portfolio to protect Facebook 's interests over the long term."

"Today's agreement with Facebook enables us to recoup over half our costs while achieving our goals from the AOL auction," said Brad Smith, executive vice president and general counsel at Microsoft.

The deal is expected to give Facebook a stronger position in the technology patent battlefield, where the company had been weak and facing lawsuits, most notably from Yahoo.

Late last month, Facebook was said to purchase 750 patents covering software and networking from IBM, according to a Bloomberg report.

Before this, Facebook had around 56 issued patents of its own and 503 filed U.S. patent applications.

Yahoo sued Facebook over 10 patent infringements in early March, covering Internet privacy, advertising and information sharing. Facebook filed a countersuit against Yahoo on April 3.

Microsoft got the AOL patents in "a competitive auction" on April 9 for 1.056 billion dollars in cash. The patent portfolio spans technologies like advertising, search and social networking.