Algerian state-owned oil and gas group Sonatrach declined to comment on a report it has offered Banco Santander 5.7 billion euros ($8 billion) for its 30% stake in Cia Espanola de Petroleos.
El Economista said the acquisition of the stake in Cepsa, which controls 20% of the Medgaz pipeline between the North African country and Spain, would give Sonatrach total control of the pipeline.
According to the newspaper, other core Cepsa shareholder Total, with about 49%, would back the sale of Santander's stake to Sonatrach.
A Total spokesperson declined to comment.