The U.S. Energy Information Administration said it accidentally released its weekly petroleum inventory data early on its website on Thursday due to a "system malfunction."
The weekly data can trigger significant changes in the price of oil on international markets.
Thursday's EIA report showed the biggest weekly decline in U.S. crude stockpiles since September 2004.
The EIA said it was working to avoid future early releases of the data and would announce changes to its system by Monday.