Iran nuclear talks
US President Barack Obama speaks about the framework agreement on Iran's nuclear program announced by negotiators in Switzerland during a statement in the Rose Garden of the White HouseMike Theiler/Reuters

The White House is aggressively campaigning to sell the Iran nuclear framework deal which was struck by the world powers and Tehran following marathon talks.

Top US authorities right from President Barack Obama to other administration officials are trying to sell the nuclear deal to the Republican-led Congress.

"I did see some ratcheted up rhetoric on the fringes, but I actually think that most of the response here we found reassuring. We have found that both Republicans and Democrats alike have shown a thoughtful response. They want to take a look at the details. That's something that we appreciate," White House spokesperson Eric Schultz told reporters.

The P5+1 powers comprising the US, the UK, France, China, Russia and Germany signed the landmark nuclear agreement with Iran bringing to an end the 12-year-long impasse.

In an interview with CNN, White House spokesperson Josh Earnest said: "In just the last 24 hours we've had everybody from the president to the White House chief of staff, to officials at the Department of State and the Department of Defense briefing members of Congress to make sure they understand exactly why we believe this is a framework agreement that puts us on the path of making sure that we're preventing Iran from obtaining a nuclear weapon and putting in place inspections to verify that that's actually the case."

Despite the forceful campaign, the nuclear agreement has attracted sharp criticism from a few including Republican White House hopefuls.

The Republicans have said the accord fails to prevent Iran from attaining nuclear weapons capability.

"The initial details appear to be very troubling. Tehran is gaining international acceptance of its nuclear ambitions and will receive significant sanctions relief without making serious concessions," Florida Senator Marco Rubio, one of the four Senate Republicans who plans running for the White House, said shortly after the deal was announced.

Similar criticisms have been heard from other Republicans echoing the strong disapproval by Israel.