MANAMA, Bahrain—Iranian Foreign Minister Manouchehr Mottaki on Saturday dampened the possibility for a breakthrough in next week's scheduled international talks over Tehran's nuclear program, blaming Washington for pursuing a confrontational policy towards his country instead of genuine diplomacy.

Mr. Mottaki—speaking at a regional security conference here a day after U.S. Secretary of State Hillary Clinton said Washington remained committed to negotiations with Tehran—said that his government wouldn't back down from its policy...