Facebook is spending 550 million dollars for a block of AOL patents in conjunction with Microsoft, the companies announced on Monday.

The deal came less than two weeks after Microsoft paid the struggling Internet company more than 1 billion dollars for a trove of AOL patents, which Facebook will now be licensed to use.

The deal bolsters the alliance between Facebook and Microsoft as both attempt to compete with the likes of Apple and Google. It also underlines the increasing intensity of a raging patent war among the major technology companies, which has seen Yahoo sue Facebook for alleged patent violations.

Under the terms of the deal, Facebook will buy 650 of the 925 patents that Microsoft bought from AOL and would have licenses to use the remaining 275 patents.

“Today’s agreement with Facebook enables us to recoup over half of our costs while achieving our goals from the AOL auction,” Brad Smith, executive vice-president and general counsel at Microsoft, said in a statement.

“This is another significant step in our ongoing process of building an intellectual property portfolio to protect Facebook’s interests over the long term,” Ted Ullyot, general counsel of Facebook, said in a statement.