Russian Deputy Foreign Minister Sergei Ryabkov says United Nations chemical weapons investigators are expected to return to Syria on Wednesday.
The U.N. team led by Ake Sellstrom completed a two-week probe in Syria earlier this month, but focused largely on a deadly attack in the Damascus suburbs.
Their original mandate was to investigate three earlier attacks, including one in March outside of Aleppo that the Syrian government and rebel fighters blamed on each other.
The inspectors have been tasked with determining whether chemical weapons have been used, but not to assign blame.
The attack outside Damascus sparked international condemnation and led to a plan to remove Syria's chemical weapons stockpile. The U.N. Security Council has been discussing a resolution to enforce that plan, and Ryabkov said Tuesday that Russia is hopeful an agreement will be reached this week.
Interactive map of chemical weapons destruction sites
Russia and China have opposed a push by the United States, Britain and France to include the threat of military intervention if Syria failed to give up its chemical arsenal.
Meanwhile, aid groups are urging world leaders meeting at the United Nations this week to give more aid to Syrian refugees, saying their funding appeals are falling short.
A coalition of 14 humanitarian organizations issued a statement in New York Monday saying many Syrian refugees are being left to fend for themselves, without adequate food, shelter and medicine.
They say an estimated 70 percent of Syria's refugees are moving into villages and cities rather than formal camps.
The groups also note the overwhelming numbers of refugees, saying that more than 50,000 Syrians arrived in northern Iraq during a single week last month. They say around 75,000 Syrians arrive each month in Lebanon and now make up one-fifth of that country's population.
Syria's civil war has forced 2 million people to flee the country, with another 4.5 million people displaced within Syria. In total, the conflict has forced more than a quarter of Syria's population to leave their homes.
Most of those who have fled the country have gone to neighboring nations, including Jordan, Lebanon, Turkey and Iraq.