U.S. says nuclear deal needed for lifting of all Iran sanctions

VIENNA (Reuters) - The United States would like to see all sanctions on Iran lifted but that can only happen "in total" after a comprehensive deal on Tehran's nuclear programme is reached, a senior U.S. official said on Thursday. The official, speaking after Iran and six world powers agreed a framework for negotiations on the nuclear dispute in coming months, also said that Washington wants "companies to be mindful and thoughtful about what they're doing", when asked about Western firms interested in doing business now with Iran. Most U.S. and other sanctions on Iran remain in place after a limited easing that took place under an interim agreement reached between Iran and six world powers in November, the U.S. official told reporters. (Reporting by Louis Charbonneau and Fredrik Dahl)