EU foreign affairs chief Federica Mogherini will visit Iran and Saudi Arabia next week following the agreement she helped broker with Tehran on its contested nuclear programme, her office said Thursday.

The talks in Saudi Arabia on Monday will cover "regional issues, in the aftermath of the agreement reached on 14 July on the Iranian nuclear issue, as well as international issues of common interest," a statement said.

In Iran, Mogherini's visit Tuesday "will provide an opportunity for exchanges on the implementation of the agreement, on which the High Representative will continue to play a coordinating role, and on regional and bilateral issues," the statement added.

The EU played a leading role in talks between Britain, China, France, Russia, the United States, Germany and Iran, holding the ring during years of tortured negotiations which finally produced an accord last week on preventing Tehran from acquiring a nuclear weapon.

In return, the powers agreed to lift damaging economic sanctions as long as Iran sticks to a deal they hope will eventually normalise ties with Tehran after years of intense distrust over its nuclear programme.

Mogherini hailed the accord as a "sign of hope for the entire world."

"It is a decision that can open the way to a new chapter in international relations and show that diplomacy, coordination, cooperation can overcome decades of tensions and confrontation," she said after the talks concluded in Vienna.

- German, French visits -

Earlier this week, German Vice Chancellor Sigmar Gabriel became the first top Western official to visit Iran after the nuclear deal.

Gabriel, who is economy minister and deputy to Chancellor Angela Merkel, said the accord paved the way for improved political and economic ties but his talks were marked by sharp differences over Israel, which Iran does not recognise.

French Foreign Minister Laurent Fabius said Tuesday he planned to visit Iran "next week" and expected to hold talks with President Hassan Rouhani.

"I will be there next week," Fabius told French radio. "My colleague (Mohammad Javad Zarif) invited me. I was invited before but didn't go but now I think everything is in place for me to go."

Fabius, who took a very hard line during the nuclear talks on getting cast-iron commitments from Tehran, did not give a date for his trip but aides said it would likely be on Wednesday.

France used to have a strong presence in Iran before sanctions, with automakers Peugeot and Renault major players in the auto industry while energy giant Total was heavily involved in the oil sector.

Britain also used to have extensive economic links with Tehran.

Iran says it needs tens of billions of dollars of investment and western technology to make up for the years lost and to revive its key oil, gas and petrochemical industries, which have suffered especially badly from sanctions.