EU commissioner in Iran aiming to preserve trade ties
Canete said preserving the deal, despite the US decision to withdraw, was "fundamental for peace in the region".
"For sure there are clear difficulties with the sanctions," Canete said at a press conference alongside Iran's Atomic Energy Organisation head Ali Akbar Salehi.
"We will have to ask for waivers, for carve outs for the companies that make investments."
Canete is due to meet Environment Minister Isa Kalantari and Oil Minister Bijan Namdar Zanganeh later on Saturday, as well as Foreign Minister Mohammad Javad Zarif on Sunday.
Salehi acknowledged Europe's efforts to maintain the nuclear deal.
"We see the European Union... is making an extensive effort. They have promised to do so, and God willing, they will put that into practice," Salehi told reporters.
European leaders have been scrambling to maintain the deal and preserve their business interests in Iran despite the risk of secondary US sanctions.
However, several of their companies - including France's Total and Holland's Maersk - have already said it will be impossible to stay in Iran once US sanctions are fully reimposed over the next six months, unless they receive explicit exemptions from Washington.
Iran's trade with the European Union is around 20 billion euros.
Iran has the world's fourth-biggest oil reserves and second-biggest gas reserves in the world. Most of its oil currently goes to China and other Asian countries. The vast majority of EU purchases from Iran - 90 percent - is oil purchases, going primarily to Spain, France, Italy, Greece, the Netherlands and Germany.
China and Russia - the other parties to P5+1 nuclear deal - have also vowed to maintain trade with Iran, and because they are less exposed to US markets, are less vulnerable to economic pressure from Washington.