UN mission 'last chance' for Syria
Russian president Dmitry Medvedev has told the UN and Arab League envoy to Syria that his mission "may be the last chance for Syria to avoid a protracted bloody civil war".
He also told Kofi Annan that he has Russia's full support.
Mr Annan was in Moscow for meetings with Russia's president and foreign minister.
He now travels to China, which with Russia has shielded Syrian leader Bashar Assad from United Nations' sanctions.
Syria is Moscow's last remaining ally in the Middle East and is a major customer for Russia's arms industry, but Russia has recently shown impatience with Assad.
Thousands have died in the year-long uprising against Assad's regime.
Syrian forces have attacked flashpoint areas, carrying out raids and clashing with rebels. Activists reported clashes in Daraa, the southern province where the uprising began last March.
A spokesman for the rebel Free Syrian Army, Muneef al-Zaeem, said government troops invaded the town of Nawa, with a population of 100,000.
Seeking to stop the violence, the US and other key allies are considering providing Syrian rebels with communications help, medical aid and other "non-lethal" assistance.
President Barack Obama discussed the aid options in a lengthy private meeting with Turkish prime minister Recep Tayyip Erdogan. The leaders are in Seoul, South Korea, for a nuclear security summit.