Crude oil prices recovered lost territory in Thursday trading as the European Central Bank said it was keeping its interest rates unchanged.

Oil prices at the opening bell in New York showed some investors may be seeking bargains in the weakened energy market. A string of reports this week indicated markets still favored the supply side, though crude oil staged an early Thursday rally.

Brent crude oil gained nearly a full percentage point from Wednesday's close to start the trading day at $48.30 per barrel. West Texas Intermediate, the U.S. benchmark for crude oil, was up 1.1 percent from the previous session to $45.20 per barrel.

Concerns about spillover from Greek debt crises unsettled market watchers concerned about European economic momentum early this summer. The governing council of the European Central Bank said it was keeping interest rates at near-zero. In remarks late Wednesday, European Commissioner for the Euro and Social Dialogue Valdis Dombrovskis deferred policies to ECB President Mario Draghi.

"The European Central Bank is using its monetary policy tools to their full potential," he said. "After all, it was famous Mario Draghi's 'whatever it takes' [comment] that helped to calm financial instability in the Euro area."

Crude oil prices dropped in late September after Eurostat, the statistics office for the European Union, said regional annual inflation of -0.1 percent for September was a contraction from the 0.1 percent reported the previous month.

Oil prices are down about half from this time last year as supplies continue to outweigh demand from a world economy still struggling to gain traction after the latest recession. No decision on production was made during a meeting in Vienna between producers in and outside of the Organization of Petroleum Exporting Countries.

For Russia, where low oil prices are creating economic strains, OPEC's decision was met with a degree of frustration.

"OPEC has fully stopped performing its function of the regulator," Igor Sechin, the head of Russian oil producer Rosneft, said.