MOSCOW – Russia urged the Syrian government and the United Nations on Thursday to agree on a visit by chemical weapons experts to the site of an alleged gas attack by troops loyal to President Bashar al-Assad that killed hundreds of people.

Syria's opposition has demanded that U.N. inspectors, who are already in the country to examine previous claims of chemical weapons use in its civil war, investigate the rebel-held region where the attack was said to have occurred.

Russia, Assad's strongest ally during the more-than-two-year-old conflict, has said that civilians were killed by "a homemade rocket loaded with an unidentified chemical agent" and that the attack was likely a provocation by opposition forces meant to place blame on the Syrian president.

Russian Foreign Ministry spokesman Alexander Lukashevich said Syria's position on sending inspectors to the site of the reported attack should be respected but dismissed the suggestion that Russia would object to such an investigation.

"The group of observers are already in place. Such a position was agreed upon in the U.N. Security Council. How can we object? We, quite the opposite, have an interest in the investigation into what happened happen objectively," he said.

"(The United Nations and Syria) have agreed on cooperation in three areas. If there is a need to achieve clarification in this case - and judging by everything, there is - then they need to agree," he told a news conference.

Syria's government offered no immediate public response to calls on Thursday for the U.N. team to have access to the area.

Damascus has called the allegations against its forces "illogical and fabricated", pointing to the timing of the attack and its previous assertions that, if it possessed chemical weapons, it would never use them against Syrians.

With the death toll from Wednesday's incident estimated between 500 and 1,300, what would be the world's most lethal chemical weapons attack since the 1980s prompted an emergency meeting of the U.N. Security Council in New York.

Russia, one of the biggest suppliers of arms to Damascus, has protected Assad during the conflict, vetoing U.N. sanctions aimed at pressuring him to end violence. Moscow has also demanded that a U.N. investigation into the alleged use of chemical weapons in Syria also look into possible use by rebels.