Syrian regime air strikes killed at least five civilians in a rebel-held neighborhood of Aleppo city, the Syrian Observatory for Human Rights said calling it a "serious violation".

The raids follow a lull in strikes brought by an unprecedented ceasefire that has largely held since coming into force on February 27.

Leading French daily Liberation on Friday published an edition entirely produced by Syrian journalists, photographers and writers to mark five years since the start of their country's devastating war.

The name of the newspaper is written in Arabic, "Tahrir" (Freedom), alongside a cartoon by Syrian Juan Zero showing children riding a merry-go-round on the tip of a bomb, all in black against a red background.

A new round of talks aimed at ending the war in Syria will begin in Geneva on March 14 and will last no longer than 10 days, the U.N. mediator said Wednesday.

Staffan de Mistura said participants would begin arriving in the coming days and that he would be having some informal talks over the weekend.

A new round of talks aimed at ending the war in Syria will begin in Geneva in earnest no later than March 14, a spokeswoman for the U.N. mediator said Tuesday.

U.N. Special Envoy for Syria Staffan de Mistura has said the new round of indirect talks between Syria's warring sides will officially start on Wednesday, but that they would likely not get seriously under way immediately.

Thomas Webber stoops to check his car for bombs every morning before heading out, but the 71-year-old American has no plans to leave Damascus, a city he has called home for more than four decades.

He is one of the very few Americans not of Syrian origin — perhaps the last one — living in the capital, after the United States closed its embassy and urged citizens to leave the country in 2012. The Czech Embassy, which has handled U.S. interests since then, told him to be careful.

The United Nations began delivering aid to three rebel towns east of Damascus on Friday, in the second distribution of assistance since a shaky truce began in Syria.

Speaking to reporters before entering the Eastern Ghouta opposition bastion, U.N. chief aid coordinator Yacoub El Hillo said the convoy included food, medical supplies and nutrition products for children.

Tens of thousands of displaced Syrians along Turkey's border have not returned home despite a truce that began at the weekend, a humanitarian organization said on Friday.

"Some 100,000 people gathered near the border -- including 50,000 in past weeks after the spike in violence in early February from the Syrian government coalition -- have not yet started to return home because it's too dangerous," the head of Medecins Sans Frontieres (MSF), Joanne Liu, told AFP.

For the first time in years, hundreds of Syrians nationwide took advantage of a nearly week-long ceasefire on Friday to resume anti-government protests under the slogan "The Revolution Continues!"

Waving the three-starred tricolor flag that has become the uprising's emblem, demonstrators in opposition-held areas of Aleppo, Damascus, Daraa and Homs called for the downfall of President Bashar Assad's regime.

French President Francois Hollande and British Prime Minister David Cameron on Thursday called on Russia and the Syrian regime to "immediately stop attacks on the moderate opposition".

In a declaration after an annual summit in northern France, the two leaders urged all parties to stick to a ceasefire and halt human rights violations.

Syria's ceasefire has shown clear signs of progress, the top U.N. envoy for the war-ravaged country said Thursday, but warned there was no guarantee it would succeed.

"The situation... on the ground could be summarized as fragile. Success is not guaranteed, but progress has been visible," Staffan de Mistura told reporters in Geneva as the cessation of hostilities entered its sixth day.