But European Union foreign policy chief says talks in Turkey produced no "great breakthrough".
Iranian nuclear negotiator Ali Larijani said on Thursday Iran and the EU were nearing "a united view" in some areas of their talks to break an international impasse over Tehran's nuclear fuel programme.
European Union foreign policy chief Javier Solana said the talks had been constructive and conducted in a good atmosphere, though no "great breakthrough" was on the cards.
Larijani and Solana spoke at a news conference in Turkey's capital before resuming discussions. They planned to break off later in the day and reconvene in two weeks' time.
The United States and other Western powers suspect Iran has a secret nuclear arms programme, and U.N. sanctions have been imposed on Tehran. Iran says its drive to produce uranium fuel is for electricity only and is vital to economic development.
Larijani, also Iran's powerful security council chief, and Solana gave no specifics of the talks, the first in two months.
It was not clear whether they found any basis for compromise on the core dispute - Iran's refusal to suspend any part of efforts to enrich uranium against a U.N. demand that it halt all such activity to win a suspension of sanctions against it and launch negotiations leading to trade benefits for Iran.
Some diplomats and analysts have said Iran and six world powers handling Iran's nuclear file could accept a partial enrichment suspension under strict U.N. inspections to break the deadlock, but both sides have publicly denied this.
Larijani and Solana suggested to reporters that progress was made in reconciling what Iran calls its drive for peaceful nuclear energy with the fear of world powers that Tehran has a clandestine agenda to assemble atomic bombs.
"APPROACHING UNITED VIEW"
"In some areas we are approaching a united view. That is to say that the best approach is to settle all the issues through negotiations based on law and international rules and regulations," Larijani said.
"The International Atomic Energy Agency inspections should remain in place and the Non-Proliferation Treaty should prevail. These are good frameworks serving as focal points of unity in both sides' views," he said in comments translated from Farsi.
"We have tried to understand each other better, and that without any doubt is a very fundamental part of the resolution of the problem," said Solana.
"We have not made miracles but have tried to move the dossier forward a little bit."
He also cautioned that the Ankara talks constituted only preparatory work that could lead back to formal negotiations.
Diplomats say the key to a breakthrough may be finding a definition of an enrichment suspension both sides could stomach. This could, for example, mean suspending uranium fuel production but exempting the building or testing of centrifuge machines.
Earlier this week, Iranian President Mahmoud Ahmadinejad deflated faint hopes of swift progress in Ankara by vowing no halt to enrichment.
Larijani had said "irrational" Western preconditions - a reference to U.N. Security Council calls for shelving all enrichment activity - had thwarted diplomatic efforts to head off what some fear could be a slide into U.S.-Iranian conflict.
Despite the positive signs in Ankara, senior officials in Tehran said Iran would strike U.S. interests around the world and Israel if attacked over its nuclear programme.