Syria has reached a "critical moment" as the world awaits news of fresh peace talks, China's foreign minister told the warring nation's opposition leader Ahmad Jarba in Beijing Wednesday.

Wang Yi was speaking at the start of four days of talks with a delegation led by the head of the Syrian National Coalition.

"The current situation in Syria has reached a new critical moment," Wang told Jarba at the foreign ministry in Beijing.

"The international community has been expecting a third round of talks and China would like to contribute," he added, referring to an expected resumption of negotiations following two abortive rounds of peace talks in Switzerland.

"This is the first time for us to visit China and we have placed our hope on it," Jarba told Wang.

Beijing routinely voices opposition to interference in other countries' domestic affairs and strongly opposes foreign military action over Syria, regularly calling for a "political solution" to the crisis.

China has previously hosted both opposition and government delegations and has routinely called for dialogue between the warring sides.

More than 150,000 people have been killed in Syria since the conflict broke out in March 2011, according to the Syrian Observatory for Human Rights.

Members of the United Nations Security Council on Tuesday viewed graphic pictures taken in Syria by a former military police photographer that showed what appeared to be evidence of brutal torture, including eye gougings, strangulation and long-term starvation.

The informal council meeting was organized by France to give the 15 member states a chance to see some of the 55,000 photographs that former war crimes prosecutors have described as "clear evidence" of systematic torture and mass killings in Syria's three-year-long civil war.

French UN Ambassador Gerard Araud told reporters after the closed-door session it was important for the Security Council to see such horrific images as his delegation prepares a resolution that would refer the Syrian conflict to the International Criminal Court for possible war crimes indictments.

"The council fell into silence after we displayed the images," Araud said. "Members were truly moved."

US Ambassador to the UN Samantha Power expressed a sense of horror after attending the informal council meeting.

"The gruesome images of corpses bearing marks of starvation, strangulation and beatings and today's chilling briefing indicate that the Assad regime has carried out systematic, widespread and industrial killing," she said, referring to Syrian President Bashar al-Assad.

"The perpetrators of these monstrous crimes must be held accountable, and the international community must unite in the face of such horrors," she said.

Agencies