The Russian Embassy to Syria has denied having any evidence to support media reports that the Syrian military has used chemical arms against rebels in a recent battle.
"Our official position is such that, by this moment, there is no information at our embassy on any instances of use of chemical weapons either by the Syrian army or by opposition forces," embassy spokesman Sergei Markov told Interfax in reference to fighting in the city of Homs.
Nor does the embassy know of any other instance of use of chemical arms by the regime of President Bashar al-Assad ever since the start of the crisis, he said.
Earlier on Monday, Qatar-based television channel Al-Jazeera said, citing Homs opposition activists, that Syrian air force fighter jets dropped poison gas-containing bombs on the city's al-Bayada district, killing seven and injuring dozens of people.
The channel showed a man on life-support in hospital who was an alleged gas victim.
Israeli newspaper Haaretz said four people had been blinded and four others paralyzed as a result of the reported gas attack. Haaretz cited Syrian opposition activists as saying the gas had not been identified yet but that Syrian doctors had traced indications of sarin.
The leader of opposition group Arab Reform Initiative claimed there was highly credible evidence that chemical weapons were used in Homs.
"I have heard news from Homs, I'm very anxious - I think this is true. We have quite serious sources. By this moment, we have information that seven people were killed by suffocating gas," Bassma Kodmani told Interfax by phone.
Asked whether her sources could confirm it was the military and not the rebels who had used the alleged chemical weapons, Kodmani said: "The rebels don't have any such weapons."
"I think that the UN Security Council must investigate this. We have heard from all members of the UN Security Council, including Russia, that use of chemical weapons would mean political suicide, as the Russian foreign minister, Sergei Lavrov, said yesterday," she said.
She evaded a question whether she wanted the Security Council to order new sanctions against Assad or to give the go-ahead to foreign military intervention. "The measures must be adequate, but it is the UN Security Council that must decide what specific measures should be taken. I can't speculate or give recommendations about it," she said.
The Times of Israel, an Israeli English-language daily, quoted Syrian general Adnan Sillu, who defected to the West earlier this year, as saying Syria's chemical arsenal "has reached similar levels to Israel's nuclear weapons."
UN Secretary-General Ban Ki-moon demanded calling Assad to account if the reports on the alleged use of chemical arms are confirmed.
At the same time, the Syrian ambassador to the United Nations, Bashar Jaafari, excluded the possibility of Syria's government using chemical weapons under any circumstances.