AMMAN - Syrian forces opened fire with live ammunition on demonstrators in Damascus overnight, wounding at least four, activists said early on Tuesday as unrest continued to spread in the capital.Demonstrations and clashes with security forces have hit Damascus in the past week, undermining President Bashar Assad's argument that an 11-month uprising has been the work of saboteurs and limited mainly to the provinces.Elsewhere, an activists' group in Kfar Tkharim near the Turkish border said rebels had killed five soldiers and captured two in an ambush on a government column.Opposition activists said five people had been killed in government shelling of Homs's Baba Amro district on Monday, adding to a reported death toll of several hundred since the operation began there on Feb. 3.And activists in the western city of Hama said troops, police and militias had set up dozens of roadblocks, cutting neighborhoods off from each other.Call for ceasefireThe Geneva-based International Committee of the Red Cross, the only international organization deploying aid workers in Syria, said it was in talks with the authorities and opposition fighters for a ceasefire to bring life-saving aid to civilians.Diplomatic sources said it was seeking a two-hour ceasefire in hotspots including Homs. Residents there say they are running out of food, water and medicine after weeks of bombardment by Assad's forces.Western and Arab countries who are seeking Assad's downfall are preparing an explicit gesture of support for his opponents.US Secretary of State Hillary Clinton said the "Friends of Syria" group, meeting in Tunisia, would "demonstrate that Assad's regime is increasingly isolated and that the brave Syrian people need our support and solidarity".But Assad, who has received support from Russia, China and Iran, is forging ahead with plans to hold a referendum on Sunday on a new constitution, which the opposition dismisses as a stunt to cling to power."We'll send a clear message to Russia, China and others who are still unsure about how to handle the increasing violence but are up until now unfortunately making the wrong choices," Clinton said in Mexico at a meeting of the "G20" world powers.Germany said the European Union would probably impose more sanctions against Syria in the coming week. Western sanctions have so far had little impact without support from Russia and China for measures at the U.N. Security Council.Assad seeks supportAssad met a senior Russian politician in Damascus on Monday, who reiterated Moscow's support for his self-styled reform program and spoke out against any foreign intervention. China accused Western countries of stirring up civil war.Nevertheless, the Arab League, which has suspended Syria and called for Assad to step down, said there were signs that Russia and China could temper their support for him."There are indications coming from China and to some extent from Russia that there may be a change in position," League Secretary-General Nabil Elaraby told a news conference in Cairo.Russia and China vetoed a draft UN Security Council resolution this month that would have backed an Arab plan calling for Assad to step down. The two countries also voted against a non-binding resolution in the General Assembly last week that backed the Arab plan.Russia's ambassador to the United Nations said Moscow would soon offer proposals on humanitarian relief for Syria in the Security Council, but gave few details."It seems to me that it would be possible now to take concrete steps aimed at resolving humanitarian issues, relying on the fact that very recently, a few days ago, Damascus allowed the International Red Cross to deliver humanitarian aid to certain regions that ended up in the conflict zone," Vitaly Churkin told state-run Rossiya-24 television in an interview."It can be expected that in the coming days, Russia will put forward certain proposals on that account in the Security Council."Assad's government says it is battling a foreign-backed insurgency by terrorists, and that it is are committed to meeting real demand for democracy with the referendum on a new constitution, leading to multi-party elections within 90 days.The West and Syrian opposition figures have dismissed the plan as a joke, saying it is impossible to have a valid election amid the continuing repression.International diplomacy showed no sign of finding a solution, as Western powers and the Arab League prepared a meeting of "Friends of Syria" on Friday to pressure Assad to step down, while Russia and China backed Assad's reform plans, derided by Syria's opposition."There were hundreds of demonstrators at the main square of Hajar al-Aswad (neighborhood), and suddenly buses of security police and shabbiha (pro-Assad militia) turned up and started firing into the crowd," activist Abu Abdallah told Reuters by telephone.He said the four wounded were taken to be treated in homes.Footage posted on YouTube, purportedly taken before the shooting, showed a crowd marching in Hajar al-Aswad carrying placards in support of the besieged city of Homs and singing "Eyes are shedding tears for the martyrs among Syria's youth."