Syria's devastating conflict entered its third year on Friday with no agreement among EU leaders on British and French calls for an easing of the bloc's embargo to allow arms supplies to the rebels.
With several member states expressing strong opposition, EU leaders at a summit in Brussels put off further discussions on the future of the arms embargo until a meeting of the bloc's foreign ministers in Dublin next week.
EU president Herman Van Rompuy said that leaders had discussed easing it and "agreed to task our foreign ministers to assess the situation as a matter of priority" at the Dublin talks.
Van Rompuy said the 27 heads of state and government "discussed the dramatic situation in Syria and reaffirmed the EU's full engagement in international efforts to end the intolerable violence."
"The question of the arms embargo was raised by some members," he added.
Both London and Paris had warned they were ready to break ranks with their European partners to supply weapons to the rebels as their frustration mounts over the failure of diplomacy to end the conflict.
But there appeared little appetite from other Europeans for dropping the ban, many fearing that a flood of weapons into Syria will only escalate the bloodshed.
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.
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.
Demonstrations were held in protest centres across Syria to mark the anniversary under the rallying cry: "Two years of sacrifice towards victory".
"Despite all the killing and destruction, I have hope for the country," said Abu Ghazi, an activist in the flashpoint central city of Hama.
"There is a lot of violence, but two years into the revolution, we realise how far we have come."
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, with a daily tally of between 100 and 200 dead.
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.
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 Khaldiyeh, the Syrian Observatory for Human Rights said.
Troops also pounded south Damascus and towns around the capital, leaving at least 15 people dead, the Britain-based watchdog added.