UPDATE 2-Brazil's Petrobras says made no decision on acquiring control of Braskem

(Recasts with comments from Petrobras)

SAO PAULO, May 15 (Reuters) - Brazilian state-run oil company Petrobras said on Monday it made no decision on a potential increase in its stake in petrochemical firm Braskem, after local media reported it was mulling buying out its partner Novonor.

The firm said in a securities filing its board and management made no decision regarding "the process of disinvestment or stake increase in Braskem."

Newspaper Folha de S.Paulo reported earlier on Monday that the firm was considering acquiring Braskem's shares owned by Novonor, formerly known as Odebrecht.

The report comes after Braskem confirmed last week that controlling shareholder Novonor had received a non-binding offer for the firm from U.S.-based asset manager Apollo and Abu Dhabi National Oil Company (ADNOC).

Braskem did not immediately respond to requests for comment.

Folha said Petrobras Chief Executive Jean Paul Prates had been floating the idea in "private talks," adding that people close to him said the move would follow President Luiz Inacio Lula da Silva's guidance of increasing state control over strategic companies.

Shares in Braskem extended losses after the news and were down more than 6% in midday trading, among the biggest fallers on Brazil's Bovespa stock index, which was near flat. Petrobras slipped 2.5%.

The state-run firm holds 47% of Braskem's voting capital, while Novonor has 50.1%. Any sale would need to be approved by Novonor's creditor banks, as its stake in Braskem is pledged as collateral. (Reporting by Gabriel Araujo; Additional reporting by Peter Frontini; Editing by Sharon Singleton and Chizu Nomiyama)