Obama, decrying such levels as yet another hardship “at a time when things were already pretty tough,” said Holder was forming the Financial Fraud Enforcement Working Group.

The task force will focus some of its investigation on “the role of traders and speculators” in the oil-price surge Obama said. The group will include several Cabinet department officials, federal regulators and the National Association of Attorneys General.

In Washington, Holder said he would press ahead with the investigation, even though he did not cite any current evidence of intentional manipulation of oil and gas prices or fraud.

“Based upon our work and research to date, it is evident that there are regional differences in gasoline prices, as well as differences in the statutory and other legal tools at the government’s disposal,” Holder said in a memo accompanying a statement announcing the task force. “It is also clear that there are lawful reasons for increases in gas prices, given supply and demand.”