In Aleppo, new unverified footage has emerged which is said to show members of the Syrian army kneeling in a long line after apparently being executed by rebels.
It is impossible to confirm the authenticity of the images. Activists say the killing probably took place late last week.
Amateur video purportedly shows renewed fighting in the city of Deir Ezzor on the Euphrates River in eastern Syria.
Rebels claim they’re targeting a building where a deadly militia loyal to the Syrian regime is operating from.
Russia maintains that most Syrians still back President Bashar al-Assad government.
Deputy Foreign Minister Mikhail Bogdanov said the regime remains “solid” but that the Syrian leader had promised Moscow that he would step aside if his population picked another leader in an election.
Russia says it still hopes a diplomatic solution to the 18-month long crisis can still be reached.
Elsewhere, there are concerns for the health of thousands of Syrian refugees who have fled the country. They are now living in camps in Turkey, Jordan and Iraq.
Many have appealed for better sanitation and medicine to prevent the outbreak of infectious diseases.
“We are facing cholera and malaria. We are stuck here. On the one hand Assad is launching military assaults, shelling everywhere. On the other hand, we are at high risk for diseases here. There are scorpions and mosquitos everywhere,” said one refugee.