WASHINGTON, Aug 16 (Reuters) - The U.S. Treasury Department issued new energy financing guidance to multilateral development banks on Monday, saying the United States would oppose their involvement in fossil fuel projects except for some downstream natural gas facilities in poor countries. The new guidance from the Treasury, the largest shareholder in major development banks including the World Bank Group and the African Development Bank, prioritizes financing for renewable energy options and “to only consider fossil fuels if less carbon-intensive options (are) unfeasible.” (Reporting by David Lawder Editing by Chizu Nomiyama) Our Standards: The Thomson Reuters Trust Principles.