Kerry to Congress: "We're at a crossroads" on Iran Secretary of State John Kerry asked Congress to hold off on levying further sanctions against Iran in testimony before the House Foreign Affairs Committee on December 10, 2013. T.J. Kirkpatrick, Getty Images Secretary of State John Kerry faced skeptical lawmakers during testimony to the House Foreign Relations Committee Tuesday, where he implored Congress to hold off on levying additional sanctions against Iran while the administration negotiates a long-term deal to curb the country's nuclear program. Democrats and Republicans have joined in a bipartisan chorus of doubt about Iran's intentions in agreeing to a six-month deal that freezes their nuclear program in exchange for limited sanctions relief. The agreement is meant to allow the U.S. and its negotiating partners in the P5+1 - Russia, China, the United Kingdom, France and Germany - time to craft a long-term agreement. Mistrust of Iranian intentions, however, has led lawmakers to threaten fresh sanctions - which could undermine the deal. At the hearing, Kerry asked members of the committee to consider the delicacy of the moment. "We're at a crossroads," he said. One path could lead to an enduring resolution in the international community's concerns about Iran's nuclear program. The other path could lead to continued hostility and potentially to conflict. And I don't have to tell you that these are high stakes. We can't ask the rest of the P5+1 and our partners around the world to hold up their ends of the bargain if the United States isn't going to uphold its end of the bargain. If we appear to be going off on our own tangent and do whatever we want, we will potentially lose their support for the sanctions themselves. Because we don't just enforce them by ourselves. We need their help. And I don't want to threaten the unity that we currently have with respect to this approach, particularly when it doesn't cost us a thing to go through this process knowing that we could put sanctions in place additionally in a week and we would be there with you seeking to do it. He said fresh sanctions might give Iranians a "public excuse to flout the agreement," a concern bolstered by comments from Iranian Foreign Minister Javad Zarif, who has indicated that his country would view new sanctions as a sign that "the entire deal is dead." And if Congress adopts sanctions, it shows lack of seriousness and lack of a desire to achieve a resolution on the part of the United States," Zarif said in has been panned by its top allies in the Middle East. Engel said any final agreement that does not completely dismantle the Iranian nuclear infrastructure would be "a devastating failure." Kerry has repeatedly insisted that U.S. and its allies" security will be enhanced by the talks, and has not strayed from its bottom line. President Obama and I have both been very clear, as every member of this committee has been, that Iran must not acquire a nuclear weapon. And it is the president's centerpiece of his foreign policy, Iran will not acquire a nuclear weapon," he said. But Kerry also admitted that he, too, shares Congress" wariness of Iran. Has Iran changed its nuclear calculus? I honestly don't think we can say for sure yet. And we certainly don't just take words at face value," he said. Given the history, we are all rightly skeptical about whether or not people are ready to make the hard choices necessary to live up to this. But we now have the best chance we've ever had to rigorously test this proposition. In a sign that the administration has had limited success in their quest to convince Congress to hold off on fresh sanctions, Senate Banking Committee chairman Sen. Tim Johnson, D-S.D., said he will hold off on any new measures. "The President and Secretary Kerry have made a strong case for a pause in congressional action on new Iran sanctions, so I am inclined to support their request and hold off on committee action for now," he said in a statement. Under secretary of state Wendy Sherman, the lead negotiator on the Iran deal, and Treasury official David Cohen are set to testify before the Senate Banking Committee Thursday.