Syrian activists say security forces on Saturday opened fire on protesters in the capital Damascus taking part in a funeral procession for people killed during a protest a day earlier.

Thousands of people participated in the procession and witnesses said one mourner was killed in the shooting.

Meanwhile, anti-government protesters stepped up their protests against the regime, with large crowds turning out in Damascus and the city of Aleppo.

The unrest took place as visiting China's Vice Foreign Minister Zhai Jun called on all sides in Syria to end the violence and expressed support for a Syrian referendum on a new constitution next week.

After a meeting with President Bashar al-Assad, Zhai said he hoped the referendum, scheduled for February 26, would go smoothly and the political reforms announced by the government would help pave the way to a peaceful resolution of Syria's 11-month-old unrest.

However, Syrian opposition leaders are refusing to talk to the government, insisting President Assad step down. An Arab League plan calls on Mr. Assad to hand power to his vice president, form a unity government and hold a presidential election. The Syrian government has rejected the plan.

China and Russia have both refused to condemn Syria over its crackdown on dissent, which has killed more than 6,000 people since last March.

The U.N. General Assembly on Thursday passed a resolution, approved by 137 of the assembly's 193 member states, calling on Mr. Assad's government to “immediately put an end to attacks against civilians.”