On the eve of fresh talks with Iran, U.S. Secretary of State John Kerry said it was unclear whether an interim agreement over its nuclear power program was within reach.
"I can't tell you whether or not we can get a deal, whether we are close," Kerry told a news conference on Saturday in the Red Sea resort of Sharm el-Sheikh, where he attended an Egyptian investment summit.
"The purpose of these negotiations is not just to get a deal, it is to get the right deal," he added.
The United States and five other major powers — Britain, Germany, France, China and Russia — will resume negotiations with Iran in Lausanne, Switzerland, from Sunday. They hope to clinch a framework agreement by the end of the month.
The two sides would then seek to negotiate by June 30 a final agreement to would curb Iran's most sensitive nuclear activities for at least 10 years. In exchange, sanctions on the Islamic Republic would gradually end.
Kerry expressed concern again that a letter to Iran last week from Republican senators may have undermined the talks.
The letter warned Iran that any deal made by President Barack Obama might last only as long as he remained in office — a highly unusual intervention in U.S. foreign policy-making.Kerry said he would assure Iranian negotiators and Europeans allies during the upcoming talks that Congress did not have the authority to change the deal.
"As far as we're concerned, Congress has no ability to change an executive agreement," Kerry said, adding that "important gaps" still remained between the sides.