The deadline set by a UN Security Council resolution for Iran, which some countries suspect is pursuing a covert weapons program, to suspend all uranium enrichment activities, expires on August 31.
The five permanent UN Security Council members and Germany drafted a package of incentives to persuade the Islamic Republic to halt work on enriching uranium, but Iran gave no definite response, saying only that it was ready for "serious talks."
The countries intend "to analyze the current situation around the Iranian nuclear program," Foreign Ministry spokesman Mikhail Kamynin said.
Kamynin also said that another stage of the UN's work on the problem would start after Mohamed El-Baradei, head of the International Atomic Energy Agency, the UN nuclear watchdog, delivers a report on what Tehran has done to comply with the resolution and the package of incentives.