The White House warned Congress Tuesday that passing new sanctions on Iran -- even with a delayed launch date -- would give Tehran an excuse to undermine an interim nuclear deal.
White House spokesman Jay Carney also warned a bipartisan coalition of senators who are suspicious of the pact reached last month and want to pile up more punishments for Tehran, that their move would be seen as a show of "bad faith" by US partners abroad.
The White House stepped up its rhetorical push to forestall new sanctions amid intense behind-the-scenes lobbying by top Obama administration officials targeting key lawmakers from both Democratic and Republican parties.
"Passing any new sanctions right now will undermine our efforts to achieve a peaceful resolution to this issue by giving the Iranians an excuse to push the terms of the agreement on their side," Carney said.
"Furthermore, new sanctions are unnecessary right now because our core sanctions architecture remains in place, and the Iranians continue to be under extraordinary pressure.
"If we pass sanctions now, even with the deferred trigger, which has been discussed, the Iranians and likely our international partners will see us as having negotiated in bad faith."
Carney argued that the passage of new US sanctions -- even with a built-in six-month delay contemplated by hawks on Capitol Hill -- would threaten the unity of the international coalition that has leveled punishing sanctions on Tehran.
Barack Obama's domestic opponents have seized on the terms of the deal to claim that it enshrines the right of Iran to enrich uranium but the White House late Tuesday issued a statement which sought to clarify the scope of any eventual final nuclear deal with Tehran.
Under the deal reached between world powers and Tehran to freeze Iran's nuclear program last month, Washington committed to "refrain from imposing new nuclear-related sanctions" for the six months during which world powers will seek to hammer out a comprehensive settlement.
Carney, however, would not say whether Obama would use his presidential veto to halt any congressional effort to impose new sanctions.