Diplomats in Vienna, meanwhile, said International Atomic Energy Agency inspectors paid a second visit to Iran's recently revealed Fordo uranium enrichment facility on Thursday.
Iran acknowledged Fordo's existence in September in a confidential letter to the U.N. watchdog, then faced sharp criticism from the U.S., Britain and France for hiding the facility for years. Iran says it is building the fortified facility as a backup in case its main plant at Natanz is attacked.
The diplomats spoke on condition of anonymity in exchange for divulging confidential information.
The United States and other nations fear Iran wants to build nuclear arms, but Tehran insists its nuclear program is peaceful.
Friday's meeting will include the U.N. Security Council's permanent members — Britain, China, France, Russia and the U.S. — plus Germany, EU foreign affairs spokeswoman Cristina Gallach said Thursday. She said it would bring together political directors — foreign ministry officials below the ministerial level — from the six nations "to take stock of the situation."
Iran announced Wednesday it would not export its enriched uranium for further processing, effectively rejecting the latest plan brokered by the IAEA. That plan aimed to delay Tehran's ability to build a nuclear weapon by sending most of the uranium needed for that out of the country.