European Union nations have agreed on an oil embargo against Iran as part of sanctions over its nuclear program. Diplomats in Brussels said that EU foreign ministers would officially adopt the measures, hashed out by member countries' 27 ambassadors, later on Monday. The measures include an immediate embargo on new contracts with Tehran for crude oil and petroleum products, while existing ones must be brought to an end by July 1. EU diplomats are calling the measure part of a twin track approach toward Iran: increase sanctions to discourage what they suspect is Iran's pursuit of nuclear weapons but emphasize at the same time the international community's willingness to talk. EU foreign policy chief Catherine Ashton said she hoped financial sanctions would persuade Tehran to return to negotiations with Western powers, which she represents in talks with Iran.