Supply concerns reversed a downward trend on oil prices yesterday and halted a spate of morning profit-taking.

Crude and gasoline futures prices started lower despite a Wednesday Energy Department report that showed a large, unexpected drop in gasoline stockpiles and a decline in refinery utilization.

Prices rebounded shortly, however, as concerns over supply returned, analysts said.

"The overall picture here is still pretty bullish," said Kevin Saville, of Platts.

Bolstering the Energy Department's warning on diminishing stockpiles were reports that gasoline-making units at four major refineries have been shut down this week for various reasons, Saville said.

"Amid all these (gasoline) stock draws, you have all these refinery problems," Saville said.

The benchmark light, sweet crude for June delivery rose 18 cents to US$66.02 a barrel in midday trading on the New York Mercantile Exchange. Gasoline futures were up more than two cents at US$2.3031.

Brent, which is not as affected by US gasoline supply issues, fell 14 cents to US$68.43 a barrel on the ICE Futures exchange in London.

International events should ease oil prices, analysts said. Iran's top nuclear negotiator said talks with a senior EU official had brought them closer to "a united view" of how to break a deadlock over Tehran's defiance of a UN Security Council demand to freeze uranium enrichment.