The European Union chief negotiator talks on Iran nuclear deal believes an agreement will be reached at the next round starting next week as the talks adjourned.

"I am sure that the next round will be the one in which we will finally get a deal," Enrique Mora, chief coordinator of the talks, told reporters as the fifth round of indirect U.S.-Iranian negotiations wrapped up on Wednesday.

Mora also said that the text of the agreement on the revival of Burjam has not been finalized yet, adding that there are still some political and technical issues that are relatively complex.

Meanwhile; Mikhail Ulyanov, Russia's permanent representative to international organizations based in Vienna, said after the end of the JCPOA joint commission meeting that the talks are going well.

Iran's top nuclear negotiator said barriers to the revival of the deal are complicated but not insurmountable. 219