Iran's foreign minister said the Syrian government had told Tehran it would allow U.N. inspectors to visit areas reportedly affected by chemical weapons, Iran's Press TV reported on Sunday.
The Syrian opposition has accused government forces of killing well over 1,000 civilians with poison gas in Damascus suburbs on Wednesday - an accusation dismissed by the government.
World powers have urged Syrian President Bashar al-Assad to allow U.N. chemical weapons inspectors already in Damascus to examine the sites.
"We are in close contact with the Syrian government and they have reassured us that they had never used such inhumane weapons and would have the fullest cooperation with the U.N. experts to visit the areas affected," Mohammad Javad Zarif told Italian Foreign Minister Emma Bonino in a telephone conversation on Saturday, according to Press TV.
Iran is Syria's closest ally and is supporting Assad against opposition forces seeking to overthrow him. The Syrian government has accused rebels of launching the chemical attacks to provoke an international reaction, an account backed by Iran and Russia, another ally.
"The international community must show a serious reaction to the use of chemical weapons by the terrorists in Syria and condemn this move," Zarif said, according to the English-language Press TV report.