A breakthrough agreement to end the standoff over Iran’s nuclear program appeared to face its first major difficulty on Friday with Russia warning that expanding a U.S. sanctions blacklist could seriously complicate the deal’s implementation. Russia, which, along with the United States, is among the six world powers that negotiated the November 24 interim accord with Tehran, echoed Iranian criticism that it violated the spirit of the deal and could “block things”. The United States on Thursday blacklisted additional companies and people under existing sanctions intended to prevent Iran from obtaining the capability to make nuclear weapons. Iran denies any such aims. Diplomats said Iran, in what appeared to be a response, interrupted technical talks in Vienna with the six nations over how to implement the agreement, under which Tehran is to curb its atomic activities in return for limited sanctions easing. The developments highlighted potential […]