Talks between Iran and six world powers on negotiating a long-term deal to limit Tehran's nuclear program have opened in Vienna.
The talks are the first round of high-level of negotiations since an interim deal struck on November 24 under which Tehran curbed some of its nuclear activities for limited international sanctions relief.
On February 17, Iran's Supreme Leader Ayatollah Ali Khamenei, however, said that he was not optimistic that the nuclear talks would produce a viable agreement, predicting that the process "will not lead anywhere."
"The nuclear issue is an excuse for their hostility. Even if the nuclear issue is resolved to the satisfaction of the Americans one day, which is extremely unlikely, another issue will follow," Khamenei said.
"Just look at what issues the U.S. government speakers keep bringing up -- human rights issues, missile issues, weapons issues, and so on. I am surprised that the Americans are not ashamed to even talk about human rights."
Hours later a senior U.S. administration official also played down expectations, telling reporters in the Austrian capital that it will be a "complicated, difficult and lengthy process" and "probably as likely that we won't get an agreement as it is that we will."
Tehran has defied UN Security Council demands that it suspend uranium enrichment and other sensitive activities, leading to a crippling sanctions imposed by the EU, the United States, and United Nations.
Analysts say Khamenei's decision to pursue negotiations with the six powers in spite of the skepticism he shares with his hard-line supporters is a result of Iran's worsening economic conditions.
Senior officials from Britain, China, France, Germany, Russia, and the United States are taking part in discussions with an Iranian delegation led by Foreign Minister Mohammad Javad Zarif and his deputy, Abbas Araqchi.
European Union foreign-policy chief Catherine Ashton will oversee the talks.
Based on reporting by AFP and Reuters