Brazil's state-owned oil and gas company Petrobras and Italy's energy company ENI on Tuesday signed an agreement to develop new technologies to produce bio-fuels on a large scale.

Brazilian President Luiz Inacio Lula da Silva and Italian Prime Minister Romano Prodi attended the ceremony to sign the document in Brasilia.

According to the agreement, the study will include the selection of supplies to the production of bio-fuels, as well as the improvement of the refining process of heavy oil in Brazil.

Petrobras said it would broaden cooperation with the ENI in refining and transportation projects, apart from exploitation and production.

During a visit to Sao Paulo on Monday, Prodi announced that Italian companies would invest 480 million U.S. dollars in the construction of four bio-diesel refineries in the country. The fuels produced by those plants will be purchased by Petrobras and foreign companies like AGIP and Europe Oil.