Brazilian state-run oil company Petroleo Brasileiro SA (PBR, PETR4.BR), or Petrobras, confirmed Tuesday that it's evaluating buying all of Italian oil major Eni SpA's (E, ENI.MI) 33.34% stake in Portuguese energy company Galp Energia SGPS (GALP.LB).

"The company reaffirms that it is constantly analyzing investment opportunities in
Brazil and abroad that are aligned with the strategies set forth in its Business Plan. Petrobras confirms that it is studying a possible business deal with ENI but up to now no conclusion was taken and there are no binding obligations between the parts," the company said in a statement.

The company didn't unveil other details.

On Tuesday,
Portugal 's daily Diario Economico reported that Petrobras offered EUR3.5 billion ($4.69 billion) to buy all of Eni's stake in Galp Energia.

According to the report, which cited an unnamed person close to the talks, the amount offered by Petrobras is lower that the initial demand of Eni. Eni wants EUR4.7 billion for its stake, or EUR17 a share, the newspaper said.

Contacted by Dow Jones Newswires an Eni spokesman declined to comment.

Eni Chief Executive Paolo Scaroni told Dow Jones Newswires in a July interview the Rome-based energy company was open to sell its Galp stake if a buyer offered a strong "premium." He highlighted Galp's presence in the expanding Brazilian hydrocarbon market as a main asset.

Scaroni has repeatedly said that Eni's ultimate plans are either to take a controlling stake in Galp or sell it, ruling out maintaining the current situation.

Eni's investment in Galp has been around EUR1 billion.

Observers note that a possible sale to Petrobras would need to clear a series of obstacles, such as Eni having to first offer to sell the stake, but only as a block, to the other members of the Galp shareholders' pact.

As of 1356 GMT, Petrobras' share was down 1.19% at 26.68 reals ($16.16) on the Sao Paulo Stock Exchange, the BMFBovespa, while in
Italy 's Stock Exchange, Eni's share was up 1.6% at EUR16.68, outperforming the 0.9% gain of Italy 's benchmark FTSE Mib Index.