Syria's devastating conflict entered its third year on Friday with EU leaders frustrated over the failure of diplomacy to end the bloodshed pressing to arm rebels despite Russian objections.
The Syrian Revolution 2011 Facebook page, a key driving force behind the uprising, has called on people to demonstrate after the main weekly Muslim prayers under the rallying cry "Two years of sacrifice towards victory".
The conflict erupted on March 15, 2011 when protesters inspired by Arab world uprisings took to the streets of cities and towns across Syria for unprecedented demonstrations to demand democratic change.
Despite the demonstrators being unarmed, peaceful and made up of many women and children, forces of President Bashar al-Assad unleashed a brutal crackdown, opening fire on them and prompting an ever-growing number to take up arms.
Two years on, Syria is mired in a civil war that has killed at least 70,000 people and forced one million to flee abroad, with millions more missing or displaced, sparking an economic and humanitarian disaster.
The International Committee of the Red Cross said it was "deplorable" people were getting used to the fact so many civilians were being killed each day.
UN High Commissioner for Refugees Antonio Guterres said there was a real risk of a regional "explosion" if the conflict was allowed to drag on.
Rebels have seized large swathes of territory, but growing tensions between liberals and moderate Muslims on the one hand, and Islamists on the other, have raised fears of a collapse into a sectarian bloodbath.
In power for more than 40 years, the Assad clan believed it could quell the revolt, just as Bashar's father and predecessor Hafez did in 1982, when he crushed a Muslim Brotherhood uprising in Hama, killing between 10,000 and 40,000 people.
The military has formidable firepower, and clashes with outgunned rebels have reduced many cities to rubble.
Britain and France have announced moves to begin addressing that imbalance by lifting an arms embargo on Syria, and the issue was expected to come up again on Friday on the second and final day of an EU summit in Brussels.
"Our goal is to convince our partners at the end of May, and if possible before.... If by chance there is a blockage by one or two countries, then France will take its responsibilities," French President Francois Hollande said on Thursday.
The United States said it may look favourably on the British and French moves to give more aid to the rebels, without explicitly backing arms shipments.
However, Berlin is known to be cool to the idea with German Chancellor Angela Merkel saying the EU needed to "proceed very cautiously" on lifting the embargo.
And Austrian Chancellor Werner Faymann said his country was not prepared to lift the ban.
"We are against the end of the arms embargo. We think the delivery of arms does not contribute to a possible solution," he told reporters as the talks began on Friday.
A Spanish diplomatic source said there was widespread hesitation about supplying weapons to the rebels.
"I think the member countries don't want to follow the French position," the source said.
The Damascus government suspects neighbouring Jordan of opening its borders this month to weapons purchased by Saudi Arabia in Croatia for the rebels, a Syrian security source told AFP.
"We deplore the change of attitude of Jordan, which in the past 10 days has opened its borders and is allowing to cross over jihadists and Croatian weapons bought by Saudi Arabia," the source said.
The army on Friday resumed an assault on parts of third city Homs infiltrated by the insurgents, including Baba Amr, the Old City and Khalidyeh, said the Britain-based Syrian Observatory for Human Rights.
Troops also pounded south Damascus and clashed with rebels in the towns of Harasta and Irbin, northeast of the capital, as well as in and around second city Aleppo, in Syria's north, it added.