(RTTNews) - The United States has imposed sanctions on a Swiss subsidiary of Iran's state-owned oil company for its involvement in the Iranian petroleum sector. The State Department took the action on Naftiran Intertrade Company, or NICO, (Srl), under the Iran Sanctions Act, aimed at pressing Tehran to halt its clandestine nuclear enrichment program. In addition, the U.S. government received commitments from four major European international energy firms to terminate their investments and avoid any new activity in Iran's energy sector, delivering a heavy blow to that country. The oil companies that have pledged to end their investments in Iran's energy sector are Total (TOT) of France, Statoil (STO) of Norway, Eni (E)of Italy and Royal Dutch Shell (RDS-A: News ) of Britain and the Netherlands. http://www.rttnews.com/ArticleView.aspx?Id=1434257