US President Barack Obama has told Congress his country should not impose new sanctions on Iran if it is serious in negotiations with Tehran over its nuclear energy program. Obama-- who has been speaking to reporters in his last press briefing of the year-- has refreshed his warnings that any new sanctions against Iran could derail the current diplomatic efforts to resolve the differences with Iran. Obama says he understands why some US lawmakers want to \\\"look tough\\\" on Iran. But he says the US must give diplomacy a chance. Obama has further repeated threats that the US keeps all options on the table regarding Iran if it fails to comply to the terms of the nuclear deal that Tehran signed with the permanent members of the UN Security Council plus Germany last month. Show Less >>