SAO PAULO, May 26 (Reuters) - Colombia's state oil company Ecopetrol launched a tender offer to acquire control of Brava Energia, the Brazilian energy firm said in a securities filing late on Monday.

o Offer covers 116.1 million common shares at 23 reais per share, a 15.4% premium over Brava's Monday close

o Deal represents about 25% of Brava's total share capital

o Ecopetrol would hold 51% of Brava's shares, securing a majority control of the Brazilian company

o Companies announced the deal in April, when Ecopetrol purchased a 25% stake in Brava, triggering the tender offer

o Conclusion of the transaction will require approval from Brazil's antitrust watchdog CADE

($1 = 5.0100 reais)

(Reporting by Isabel Teles; Editing by Gabriel Araujo)