Russia on Tuesday accused Syrian rebels of using sarin nerve gas, but the U.S. dismissed these allegations and said more proof was required.
Russia's UN envoy, Vitaly Churkin, said that he handed over evidence to the United Nations which indicates that the rebels fighting to oust President Bashar Al-Assad used sarin gas in an attack in March.
According to AFP, Churkin said Russian experts had been to the scene of the attack at Khan al-Assal near Aleppo and had gathered firsthand evidence.
The Syrian government has refused to let a UN inspection team into the country, but this week invited UN officials for talks on launching an investigation.
Churkin told reporters the Russian inquiry had "established" that rebel forces had fired a Bashar 3 missile at the town, killing 26 people including 16 troops.
"The results of the analysis clearly indicate that the ordinance used in Khan al-Assal was not industrially manufactured and was filled with sarin," Churkin added, according to AFP.
Britain, France and the United States say they have handed over evidence to UN experts that it was Assad's forces who have used chemical weapons in the 26-month-old conflict.
The U.S. government, which has confirmed that the Syrian army used chemical weapons against rebel forces on multiple occasions, has said it will increase the “scope and scale” of its assistance to rebels in Syria in response.
Russian President Vladimir Putin has warned that the Syrian rebels are “cannibals” and should not be given arms, referring to video footage posted on the Internet last month of a rebel fighter eating the heart of a government soldier.
He also said that his country would not rule out sending fresh arms to the Syrian regime.
In response to Tuesday’s claims by Russia, White House spokesman Jay Carney said the United States had not seen any evidence to suggest that anyone other than the Syrian government "had the ability to use chemical weapons, or has used chemical weapons."
"If Bashar al-Assad is seriously interested in proving his assertion, and now the assertion that Russia is making, Assad should let the UN investigators in and Russia should use its relationship with Assad to press Assad to allow UN investigators in," Carney pointed out.