Director of the Atomic Energy Organization of Iran (AEOI) Ali Akbar Salehi has expressed optimism about the prospect of the nuclear talks between Tehran and the Sextet of powers, PressTV reported.
"I am optimistic about the future of the talks," Salehi told reporters on Friday.
The AEOI chief noted that the Iranian negotiators continue the talks based on Iran's national interests.
The foreign ministers of the Sextet of world powers - the United States, France, Britain, Russia, China and Germany - have been invited to join the ongoing talks on Iran's nuclear energy program in the Austrian capital city of Vienna.
On Thursday, Russia expressed hope for a permanent accord on Iran's nuclear energy program, saying it sees signs of progress in the ongoing talks between Tehran and the world powers.
On July 3, Iran and the six countries formally kicked off their sixth round of nuclear talks this year to discuss a permanent accord on Tehran's nuclear energy program.
Iran and the six countries have been discussing ways to iron out differences and achieve a final deal. The two sides sealed an interim deal in the Swiss city of Geneva on November 23, 2013. The deal came into force in January and will expire on July 20, but can be extended depending on an agreement by all the parties to talks.