Senate : Sen. Robert Byrd cites Iranian missile launch plan in calling for new sanctions . Among other things , the deal requires Iran to limit how much it enriches uranium , a step that boosts the concentration in raw ore of a specific kind of uranium isotope that is best suited to maintaining nuclear reactions . NEW : Administration officials testify that now 's not the time . Administration worries the bill could affect historic Iran nuclear deal . Secretary of State John Kerry has asked for Congress to push through the deal .
Senate : Sen. Robert Byrd cites Iranian missile launch plan in calling for new sanctions . NEW : Administration officials testify that now 's not the time . Administration worries the bill could affect historic Iran nuclear deal . Secretary of State John Kerry has asked for Congress to push through the deal .