An interim nuclear agreement between Iran and six major powers will be extended through Friday to provide more time for talks on a final agreement, the United States said on Tuesday.
"We've made substantial progress in every area, but this work is highly technical and high stakes for all of the countries involved," Marie Harf, the spokeswoman for the U.S. delegation, said in a statement.
"We're frankly more concerned about the quality of the deal than we are about the clock, though we also know that difficult decisions won't get any easier with time—that is why we are continuing to negotiate," she added.
Russian Foreign Minister Sergei Lavrov said a weapons embargo on Iran was the main obstacle still to be overcome at talks between six major powers and Tehran on its nuclear program, Interfax news agency reported.
"I can tell you that there is only one big problem in terms of sanctions—it is the problem of a weapons embargo," Lavrov was quoted as telling reporters.