Brazilian state-controlled oil giant Petrobras signed a contract over the weekend with Bolivian state-owned energy company YPFB covering petroleum exploration in Cedro, an area in eastern Bolivia, officials said.

YPFB CEO Carlos Villegas and Petrobras Bolivia chief Erick Portela signed the contract on Sunday, opening the way for the start of exploration in Cedro, YPFB said in a statement.

"In the next few days, the Brazilian oil company will present its work plan and budget to YPFB," the Bolivian energy company said.

Petrobras's investment "strengthens the intense exploration plan" proposed by Bolivian officials, YPFB said.

Cedro is in a traditional exploration zone in Santa Cruz province and sprawls over 99,775 hectares (246,358 acres).

Petrobras has secured exploration and production contracts in Bolivia's Colpa and Caranda, Rio Hondo, San Alberto, San Antonio, Monteagudo and Ingre fields.

President Evo Morales nationalized the oil industry in 2006.

About a dozen foreign oil companies, including Spain's Repsol, operate in Bolivia, which supplies natural gas to Brazil and Argentina. EFE