Congress' Iran hawks may have given up for now on new nuclear sanctions against Tehran.
But Republicans and Democrats want Iran to know more economic pressure is coming if Iran doesn't reach a comprehensive nuclear agreement with world powers this year.
Eighty-three senators have signed a letter to President Barack Obama outlining their demands. They tell him to push for a final deal that dismantles Iran's heavy water reactor at Arak and eliminates any uranium path toward a nuclear bomb.
And they say Iran must understand a diplomatic collapse would mean increased oil and trade sanctions.
While Obama hailed last year's interim nuclear pact with Tehran, many in Congress were critical. Obama staved off a new U.S. sanctions push from Congress against Iran that risked undermining negotiations.