The refusal comes one day ahead of talks between EU foreign-policy chief Javier Solana and Larijani in the Spanish capital, Madrid.
Previous meetings have failed to persuade Tehran to obey UN resolutions demanding to halt enrichment.
The West accuses Iran of seeking to build atomic bombs. But Iran insists its program is aimed at generating electricity.
At the Madrid meeting, Solana is empowered by the world's major powers -- the United States, Russia, China, Britain, France, and Germany, as well as the EU -- to explore the scope for formal negotiations on a package of economic, technological, and political initiatives if Iran suspends enrichment.
The UN Security Council has imposed two sets of sanctions on Iran since December for its failure to heed U.N. demands. The United States, which has led efforts to isolate Iran, has threatened further steps.
Concerning Iraq, Iranian Foreign Minister Manuchehr Mottaki said today that Tehran would consider continuing talks about Iraq with the United States only if Washington shows it is ready to "solve problems in Iraq and correct" its policies there.
Mottaki's remarks come two days after the U.S. and Iranian ambassadors to Iraq met in Baghdad for talks on security in Iraq -- the highest-level official public contacts between Washington and Tehran in 27 years.