GENEVA - The United States is not seeking to reopen or renegotiate the Iran nuclear deal but hopes to stay in it to fix its flaws with a supplementary agreement, US non-proliferation envoy Christopher Ford said on Wednesday.US President Donald Trump and French President Emmanuel Macron pledged on Tuesday to seek stronger measures to contain Iran, but Trump refrained from committing to staying in the 2015 nuclear deal and threatened Tehran with retaliation if it restarted its nuclear program. "We are not aiming to renegotiate the JCPOA (nuclear deal) or reopen it or change its terms," Ford told reporters on the sidelines of a nuclear non-proliferation conference in Geneva."We are seeking a supplemental agreement that would in some fashion layer upon it a series of additional rules - restrictions, terms, parameters, whatever you want to call it - that help answer these challenges more effectively."Macron said he spoke to Trump about a "new deal" in which the United States and Europe would tackle the outstanding concerns about Iran beyond its nuclear program."If we were able to meet that challenge of bringing our partners together... President Trump made it clear that his decision not to renew the sanctions waivers would be revised, and that is where I hope we are now today," Ford said.Asked if Macron had saved the JCPOA in talks with Trump, Ford said: "I hope the JCPOA has been saved in the context of the challenge that President Trump set for us, of trying to remain within the deal but in the context of moving forward with our partners on an approach that stands a pretty good chance of turning what was in effect a temporary postponement ... into a more enduring answer."Some diplomats have expressed concern that reopening the Iran deal could undermine Trump's talks with North Korean leader Kim Jong Un, which Trump has said could take place in May or June.But Ford said fixing the flaws in the Iran nuclear agreement would provide a model for other deals, including one with North Korea, which should aim for complete, irreversible and verifiable dismantlement of any nuclear threat."They (the North Koreans) have given us very hopeful and interesting signs that it may be possible to negotiate towards that end. We are determined to pursue that as best we can and make sure we have an enduring solution ... in ways we think the JCPOA did not do," Ford said.