Russia says a November 24 deadline for an international agreement to curb Iran's nuclear program in exchange for the lifting of sanctions might not be met.
Foreign Ministry spokesman Aleksandr Lukashevich on November 13 said: "It cannot be ruled out that more time could be needed to reach a mutually acceptable compromise."
Lukashevich said negotiators from Iran and six global powers -- Britain, China, France, Russia, the United States, and Germany -- have the "political will" to see a deal reached by the self-imposed deadline.
But he said there are remaining problems that will not be easy to resolve.
The six powers negotiating with Tehran want to ensure it will never develop a nuclear weapon, while Iran wants the lifting of painful economic sanctions imposed by the UN Security Council and Western governments.
Iran says its nuclear program is for power generation and other peaceful civilian purposes.
Based on reporting by TASS, Interfax, and Reuters