DAMASCUS: Damascus on Wednesday rejected a call by UN chief Ban Ki-moon for it to declare a unilateral ceasefire, insisting that rebels fighting the government must stop the violence first.

"We told Ban Ki-moon to send emissaries to the countries which have influence on the armed groups, so that they put an end to the violence," foreign ministry spokesman Jihad Maqdisi said.

Maqdisi said that twice during the abortive UN military observer mission deployed to Syria between April and the end of August, Damascus had implemented a ceasefire.

But he said the rebels "used the opportunity to expand their armed deployment and increase casualties due to terrorist activities".

He said Foreign Minister Walid Muallem discussed the issue with Ban on the sidelines of the UN General Assembly earlier this month.

Muallem told the UN chief that governments that "finance, train and deliver weapons to the armed groups, notably Saudi Arabia, Qatar and Turkey" should be stopped.

Ban urged the Syrian regime on Tuesday to declare an immediate truce to bring an end to the conflict that he said had left 20,000 dead over the last 19 months.

"It is unbearable for the (Syrian) people to continue like this. That is why I have conveyed to the Syrian government (a) strong message that they should immediately declare a unilateral ceasefire," the UN chief said.

He urged "the opposition forces to agree to this unilateral ceasefire when and if the Syrian government declares it" and he called on countries supplying arms to either side to stop in order to ease the suffering of the Syrian people.