Western powers have warned Iran of further sanctions if it rejects an incentives offer and presses on with sensitive nuclear work.
Iran yesterday ruled out suspending uranium enrichment despite the offer by six world powers of help in developing a civilian nuclear programme if it stopped activities the United States and others suspect are designed to make bombs.
European Union foreign policy chief Javier Solana said after talks in Tehran that Iran should stop enrichment during negotiations on the offer, a precondition it has repeatedly rejected.
"The deadlock is still there," one Iranian political analyst who declined to be named said after Solana's visit.
The incentives package agreed by the United States, Russia, China, Britain, France and Germany last month and delivered by Solana to Iranian Foreign Minister Manouchehr Mottaki is a revised version of one rejected by Iran in 2006.
Parliamentary speaker Ali Larijani, Iran's former chief nuclear negotiator, said the assembly would carefully study the offer and "wisely defend the nuclear rights of the nation", Iran's Press TV said on its website.
Leading member of parliament Alaeddin Boroujerdi said halting enrichment is a "red line" and will not be accepted.
Solana said he expected a reply soon from Iran, which says its nuclear programme is only for the generation of electricity, but Boroujerdi said Tehran was in no hurry.
"They will never accept the proposal as it is," one Western diplomat said. "As usual they are playing for time."