Iranian security forces have launched a campaign to arrest figures within the country's reformist movement. Reports on Monday said this widens a crackdown on dissent after authorities earlier put down nationwide protests. The protests resulted in thousands of deaths and tens of thousands more detained. Detained Nobel Peace Prize laureate Narges Mohammadi has received another prison sentence of over seven years. Media reports quoted officials within the reformist movement, which seeks to change Iran's theocracy from inside, as saying at least four of their members had been arrested. Iran and the U.S. held new nuclear talks last week in Oman.