Ali Larijani, Iran's chief nuclear negotiator, and Javier Solana, the EU foreign policy chief, said they would be in contact to discuss how to proceed after Solana reports to the five permanent members of the Security Council - the US, Britain, France, Russia and China - and Germany in Paris on Wednesday.
Larijani said there was a "long road" ahead before the situation could be resolved.
It was the second round of talks between Iranian and EU officials in five days.
The six nations had demanded a response fom Iran to the package of incentives to suspend uranium enrichment before next weekend's summit of the Group of Eight industrialised nations in Russia, otherwise it could face UN security council action.
Iran is not considering suspending uranium enrichment to resolve its nuclear stand-off with the West, an Iranian deputy foreign minister said.
Manuchehr Mohammadi said freezing uranium enrichment would not make any difference to the situation. "We did it before, we did it for two-and-a-half years," he said. "It proved that it didn't work."
Iran says it has the right to peaceful nuclear technology and enrichment.
Mahmoud Ahmadinejad, the Iranian president, said Iran would complete its nuclear fuel work and not back down "one iota" under international pressure.
"The Iranian nation is determined to obtain all of its rights, including full nuclear rights and the complete exploitation of the nuclear fuel cycle," he was quoted as saying by the ISNA news agency.
Iran has said it will reply late next month to the technological, economic and political deal.
An Iranian foreign ministry spokesman has suggested that its full answer will emerge only during detailed negotiations on the offer.
Sanctions are threatened if Iran does not accept the offer but diplomats say Russia and China, both veto-holders in the Security Council, are reluctant to back any.
Iran, the world's fourth-largest oil exporter, denies claims that it wants a nuclear weapon and says it is interested only in electricity production.