Iran on Sunday hailed the decision of its ally Syria to join the chemical weapons convention, a day after the United Nations formally accepted its request to sign up, Fars news agency reported.
"Iran welcomes Syria's joining the chemical weapons convention," it quoted foreign ministry spokeswoman Marzieh Afkham as saying.
Damascus applied on Thursday to join the convention.
Syria's membership of the convention and the related Organisation for the Prohibition of Chemical Weapons is part of a plan drawn up by Russia and the United States to head off a Western military strike.
Signup to our newsletter and follow us on Facebook and Twitter!
The United States and other Western nations accuse Assad's forces of having launched a sarin gas attack on August 21 near Damascus in which hundreds died.
The Syrian government blames opposition rebels for the attack.
Afkham demanded that Israel also be obliged to join the convention.
"It is worrying that the Zionist regime is the only one in the Middle East not to adhere to any convention on weapons of mass destruction, notably that on chemical weapons," she said.
"We demand that the UN Security Council and the international community take serious measures to make this regime join the convention on chemical weapons," Afkham added.
Israel signed the chemical weapons convention in 1993 but has never ratified it, despite demands to do so from Washington and Moscow.