Some foreigners are fighting in Syria's largest city, Aleppo, alongside rebels who say they are disappointed that more residents have not joined their cause.
Reporting from the frontline, Al Jazeera's Zeina Khodr says the young rebels in the city have come mainly from the countryside of Aleppo province.
It has not been easy to stand up against the Syrian army, especially when the city did not rise up when rebels entered some poor neighbourhoods and set up bases, she says.
"We saw a few Arab fighters from Saudi Arabia and Egypt who didn't want to be filmed," our correspondent said, adding that some of the foreign fighters claimed allegiance to al-Qaeda.
"Undoubtedly the majority of the fighters here are Syrians, but this war has attracted Arabs who feel obliged to help the opposition, who are mainly Sunni Muslims."
Al Jazeera's Khodr also says the authorities still enjoy some backing in Aleppo, either out of fear of the state or fear of an opposition that has no clear agenda apart from toppling President Bashar al-Assad.
Allepo, which is Syria's financial capital, had long been immune from the fighting in the countryside. However, now the conflict has divided the people along class and religious lines, she says.
The developments in Aleppo come amid renewed assault by the Syrian army on the southern neighbourhoods of Damascus, residents and activists said on Wednesday.
At last 40 people were killed in the shelling, which was accompanied by attacks from helicopters, and in ensuing ground raids on the Kfar Souseh, Daraya, Qadam and Nahr Aisha neighbourhoods, they said.
"The whole of Damascus is shaking with the sound of shelling," a woman in Kfar Souseh said.
She said the army's artillery was also firing on the capital from the Qasioun and Saraya mountains overlooking Damascus.
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The assault on Damascus coincide with the departure of the UN observer mission, whose members are leaving after failing to secure a ceasefire.
In towns across Syria, the suffering of war does not end with the shelling, as food and medicine shortages get worse.
At last count the UN said it knew of 170,000 refugees, but many more are unregistered. A school near the outskirts of Aleppo has become home to more than 500 people who have fled the fighting.
Valerie Amos, UN emergency relief co-ordinator, appealed on Wednesday for more funds to help a million people in need.
The plea followed a visit to the country by Amos, who is also the UN undersecretary-general for humanitarian affairs.
She said that most of the money raised so far had gone on food aid but there are other concerns.
"One is that we have the possibility of a major health impact in the country," Amos said.
"Syria as you may know produces most of its medicines in factories in Aleppo and elsewhere. They have now come under the impact of the fighting so crucial life-saving medicines are no longer available."
The Security Council organised a ministerial meeting in New York for August 30, when the last UN observers are due to leave, after the council acknowledged that international efforts to significantly reduce the violence and end the Syrian government's use of heavy weapons have failed.