The head of the UN inspection mission, Aake Sellstroem, was in talks with Damascus "on all issues pertaining to the alleged use of chemical weapons, including this most recent reported incident," a UN statement said Thursday.
The United Nation Security Council did not explicitly demand a UN investigation of the incident, although it said "clarity" was needed and welcomed UN chief Ban Ki-moon's calls for a prompt investigation by the inspection team in Syria.
"The Secretary-General believes that the incidents reported yesterday need to be investigated without delay," Ban's press office said in a statement . "A formal request is being sent by the United Nations to the government of Syria in this regard. He expects to receive a positive response without delay."
An earlier Western-drafted statement submitted to the Security Council, seen by Reuters, was not approved. The final version of the statement was watered down to accommodate objections from Russia and China, diplomats said. Moscow and Beijing have vetoed previous Western efforts to impose UN penalties on Assad.
However, Russia urged the Syrian government and the United Nations on Thursday to agree on a visit by chemical weapons experts to the site of the alleged gas attack.
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.