The U.S. joined the European Union in expanding sanctions to target Russian Arctic and shale-oil projects and further limit financing to Russian state-controlled companies, a move to put pressure on Moscow as Ukraine negotiates a long-term peace plan and closer ties to the E.U. The energy sanctions announced Friday, widely expected in recent days, will prevent Western energy firms from providing technology and services — other than financial services — to five Russian energy majors’ oil projects in the Arctic, deep offshore fields and shale, the U.S. Treasury Department said. The energy sanctions could directly impact partnerships such as Exxon Mobil Corp.’s (XOM) pact with OAO Rosneft (ROSN.MZ), one of the five firms targeted, according to U.S. officials and legal experts. The two companies have been drilling in the Arctic Kara Sea, as well as exploring for oil in a Siberian shale-rock formation. […]