Tehran will not renegotiate a landmark 2015 nuclear deal with world powers, Iran's Foreign Minister Mohammad Javad Zarif said on May 3.
"Iran will not renegotiate what was agreed years ago and has been implemented.... Also, we will reject any ratification of it," Zarif said in video posted on YouTube.
U.S. President Donald Trump has been a strong critic of the agreement, known as the Joint Comprehensive Plan of Action (JCPOA), under which Tehran agreed to limit its nuclear program in exchange for sanctions relief.
Trump has given the European signatories a May 12 deadline to fix what he calls the "terrible flaws" in the deal, threatening to effectively pull Washington out by refusing to extend waivers on U.S. sanctions if they do not do so.
Zarif said the United States has "consistently violated the nuclear deal, particularly by bullying others to prevent businesses from returning to Iran."
Meanwhile, UN Secretary-General Antonio Guterres on May 3 warned against ditching the JCPOA if it could not be replaced with a viable alternative.
"If one day there is a better agreement to replace it, it's fine, but we should not scrap it unless we have a good alternative," Guterres said in an interview with the BBC.
"I believe the JCPOA was an important diplomatic victory, and I think it will be important to preserve it. But I also believe there are areas in which it will be very important to have a meaningful dialogue because I see the region in a very dangerous position," he said.
Other signatories of the accord -- France, Britain, Germany, Russia, and China -- have urged Washington to remain a part of the deal, although the Western allies have also expressed concerns about the terms.