DOHA: Syria's exiled opposition would welcome a ceasefire later this month as proposed by the international peace envoy but responsibility lies primarily with the government, leader Abdel Basset Sayda told AFP on Tuesday.

"We would welcome any halt to the killings but we think the appeal needs to be addressed first to the Syrian regime, which has not stopped bombarding Syrian towns and villages," the opposition leader said.

Rebel fighters of the Free Syrian Army "are only acting in self-defence so it is normal that they would halt hostilities when the war machine does so," he added.

Envoy Lakhdar Brahimi has proposed a truce for the four-day Eid al-Adha Muslim holiday at the end of the month to pave the way for a political process.

The Syrian government said earlier on Tuesday that it was interested in exploring the idea but that, for a halt to the violence, the rebels and their backers would need to be involved too.

"In order to succeed in any initiative, it takes two sides," Maqdisi said in answer to a question from AFP.

"The Syrian side is interested in exploring this option and we are looking forward to talking to Mr Brahimi to see what is the position of other influential countries that he talked to in his tour," he said.

"Will they pressure the armed groups that they host and finance and arm in order to abide by such a ceasefire."

Brahimi, joint envoy of the Arab League and the United Nations, was in Cairo on Tuesday on the latest leg of a regional tour that has already taken him to Turkey and Saudi Arabia, staunch backers of the opposition, and Iran, Syria's closest ally.

Brahimi's office said that the envoy had appealed for Iranian help to broker the truce.

"He reiterated the call by UN Secretary General Ban Ki-moon for a ceasefire and a halt to the flow of arms to both sides. A ceasefire, he said, would help create an environment that would allow a political process to develop," his office said.