"We urge Lebanese politicians to show restraint and wisdom in this complex and urgent situation," the ministry said in a statement. "All efforts must be focused on preventing the escalation of the conflict."
According to various reports, the Iranian-backed Islamist group Hezbollah took control of the Muslim half of Beirut on Friday after three days of fighting with pro-government militia.
At least 11 people had reportedly been killed and 30 wounded in the worst internal clashes since the 1975-90 civil war.
"Russia will continue its efforts to help finding a peaceful resolution to the internal political crisis in Lebanon in order to ensure sovereignty, independence and unity of this unique country in the Middle East," the ministry said.
The European Union also urged calm and a peaceful resolution to the crisis, while Iran blamed the U.S. and Israel for fuelling the conflict by meddling in Lebanon's internal affairs.