SACRAMENTO, Calif. (AP) — California's attorney general is suing to block a petroleum company's attempt to gain more control over oil, fearing it could further drive up gasoline prices.

Attorney General Xavier Becerra (HAH-vee-air Bah-sehr'-ah) announced the lawsuit Thursday against Valero Energy Corporation.

Valero wants to buy a San Francisco Bay Area petroleum terminal from Plains All American Pipeline. The terminal in Martinez imports and exports petroleum products.

Becerra says the sale would mean all three Northern California petroleum terminals would be controlled by refineries who could "suffocate open competition."

One of Becerra's predecessors, Bill Lockyer, forced Valero to sell the Martinez facility in 2005 as part of an anti-trust deal after the company acquired two terminals under an earlier business deal.

Lillian Riojas, spokeswoman for the Texas-based company, did not immediately comment.