SAO PAULO, July 28 (Reuters) - Brazilian telecommunications firm Oi SA confirmed on Tuesday in a securities filing that it received a new 16.5 billion reais ($3.2 billion) bid for its mobile assets from Telecoms Tim Participacoes , Telefonica Brasil and America Movil's Claro.

Preferred shares in Oi soared 18% to a two-year high after TIM, Telefonica and Claro announced the new bid late on Monday.

Oi said it was analyzing the new offer, while keeping previous agreements with bidders. Oi has begun exclusive talks with Highline do Brasil, a portfolio company of U.S. private equity firm Digital Colony.

Oi's shares have risen more than 50% in the last two weeks.

Preferred shares in Telefonica and common shares in TIM both rose more than 3% on Tuesday.

Oi, which plans to use to sale proceeds to help exit bankruptcy protection, has not yet disclosed the amount offered by Highline.

In its new bid, TIM, Telefonica and Claro will also offer Oi a long-term contract to rent its telecom infrastructure, but the companies did not disclose further details.

($1 = 5.1650 reais) (Reporting by Carolina Mandl Editing by Chris Reese and David Gregorio)