Two European companies — a major contractor to the U.S. government and a top cell-phone equipment maker — last year installed an electronic surveillance system for Iran that human rights advocates and intelligence experts say can help Iran target dissidents. Nokia Siemens Networks (NSN), a joint venture between the Finnish cell-phone giant Nokia and German powerhouse Siemens, delivered what is known as a monitoring center to Irantelecom, Iran's state-owned telephone company.