He's appearing today before the House Foreign Affairs Committee. This, as lawmakers threaten to undermine last month's interim nuclear accord in Geneva. There, the US and world powers promised Iran USD 7 billion in sanctions relief in exchange for nuclear concessions.
The deal prohibits the Obama administration from introducing new sanctions for six months. Kerry and other US officials have warned of dire consequences if Washington breaks its word. And Iran's foreign minister has said any new package of commercial restrictions would break the deal.