As Congress debates how to curtail the role of speculators and rein in rising oil prices, a federal task force said Tuesday that it had so far found no evidence that those investors are systematically pushing up the cost of energy.

Instead, in an interim report made public on Tuesday, the task force said that its research “does not support the hypothesis that the activity of these groups is driving prices higher.”

The preliminary study concluded that the rise in oil prices over the last five years was “largely due” to fundamental factors like rapidly rising consumption and sluggish growth in energy supplies worldwide.

The analysis was headed by the Commodity Futures Trading Commission with help from six other agencies, including the Federal Reserve and the Treasury.