Comcast Corp. will purchase, from Cablevision Systems Corp.’s programming subsidiary, Rainbow Media Holdings LLC, Cablevision’s 60 percent interest in Fox Sports Network (FSN) Bay Area and its 50 percent interest in FSN New England for $570 million in cash.

Upon completion of the FSN transactions, Comcast will own 100 percent of FSN New England and 60 percent of FSN Bay Area, with the remaining 40 percent still owned by an affiliate of News Corp., Comcast said. Comcast will operate both networks, and completion of the two transactions is subject to certain closing conditions.

Rainbow Media’s portfolio includes AMC, The Independent Film Channel (IFC) and WE tv, as well as the Rainbow Sports Network. All three transactions add to Comcast’s growing regional sports programming operations.

Comcast’s recent expansion spree includes its acquisition of Patriot Media & Communications, Fandango, and the Indiana and Illinois cable systems of Insight Communications Company Inc. The company will also launch Fancast.com this summer.