Damascus: Former UN chief Kofi Annan held crux talks in Damascus on Saturday with the hopes of the world pinned on his bid to prevent a nearly year-old uprising spiralling into all-out civil war.

State media reported the start of talks between President Bashar al-Assad and Annan, on his first visit since being named international envoy on the conflict.

It came as a human rights group reported fierce shelling of Idlib in northwest Syria and a day after another 70 civilians were killed in the regime's crackdown on dissent.

Human rights watchdogs say the conflict has cost more than 8,500 lives since last March.

Emissary of the United Nations and the Arab League, Annan has the support of Damascus allies Beijing and Moscow and his mission has been welcomed by the both the Syrian government and opposition.

But Russia said its Foreign Minister Sergei Lavrov made clear to Annan at a meeting earlier in Cairo that Moscow was opposed to "crude interference" in Syria's affairs.

"A particular emphasis was placed on the inadmissibility of trampling on international legal norms, including through crude interference in Syria's internal affairs," the foreign ministry said.

Current UN chief Ban Ki-moon said that Annan would demand an immediate end to the violence and aid agency access to besieged protest cities to evacuate casualties and provide desperately needed relief supplies to civilians trapped by the fighting.

"I very strongly urged Kofi Annan to ensure there must be an immediate ceasefire," Ban said. "I also asked him to urge Assad to facilitate humanitarian assistance and access."

Ban said that Annan would seek to encourage dialogue between Assad's government and the opposition but that he would not meet opposition figures inside Syria and would not travel outside Damascus on his two-day visit.

His predecessor would meet Assad, other government officials, "civil society" representatives and aid workers in the Syrian capital, Ban told reporters at UN headquarters.

"He will be engaging with opposition leaders outside of Syria," Ban added. "There should be an inclusive political solution."

When he leaves Damascus on Sunday, Annan will travel on to neighbouring countries to press his mission to end the bloodshed, the UN chief said.