Iran and world powers, grouped under the so-called “5+1,” reached an interim deal last November whereby Tehran agreed to suspend for six months parts of its nuclear enrichment operations in return for modest sanctions relief. The two sides hope to build on those gains

in Tuesday’s talks in Vienna.

“I have said before … I am not optimistic about the negotiations. It will not lead anywhere, but I am not opposed either,” Khamenei told a large crowd during a visit to the northwestern Iranian city of Tabriz, according to IRNA.

“What our foreign ministry and officials have started will continue and Iran will not violate its (pledge) … but I say again that this is of no use and will not lead anywhere.”

Khamenei, who has the final say in state affairs, has given guarded support to efforts by President Hassan Rouhani, a relative moderate, to negotiate a way out of the nuclear impasse, which has led to international economic sanctions against Iran.

Western countries, led by the United States, suspect Iran of seeking to develop nuclear weapons. Iran says its nuclear program is entirely for civilian purposes.