The Iranian government said Cairo agreed to host a round of talks with the five permanent members of the U.N. Security Council and Germany this year. Iranian president Mahmoud Ahmadinejad is to visit Egypt next month.
The potential resumption of talks follows an Iranian notification to the International Atomic Energy Agency that it aims to install more centrifuges at its Natanz nuclear facility.
Lavrov said Thursday such a move was cause for concern.
"We, along with the other Security Council members, have called on Iran to freeze enrichment operations during the negotiations," he was quoted by state-run news agency RIA Novosti as saying.
Iran in September started operations at the Bushehr plant with the help of Moscow. Russia, under an agreement with Iran, operates and supplies fuel for the plant.
Members of the P5+1 have called on Iran to halt production of uranium enriched to 20 percent, which Iran says it needs for medical research. Western powers, however, say it's a benchmark that would make it easier to reach the 90 percent purity needed for a nuclear weapon.
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