A senior Russian diplomat says the G-8 summit's joint statement on ending the Syrian civil war will not mention whether Bashar Assad must step down from power as part of any peace settlement.

Russian Deputy Foreign Minister Sergei Ryabkov told reporters Tuesday that the eight nations have agreed they should not specify any outcome from peace talks that all agree should start soon in Geneva.

Ryabkov says the talks should aim to create a transitional coalition government for Syria, but should not predetermine whether Assad can participate in that government.

The formal Syria declaration is expected to be published later Tuesday.

Ryabkov dismissed Western claims that Assad's forces used chemical weapons as unproven and said they require further investigation.