At least 13 people were killed across Syria on Saturday as fierce fighting raged in Aleppo and Damascus, the country's two biggest cities, a rights group said.

Overnight in Aleppo, rebel forces withdrew from the district of Izaa where the state television building is situated, according to the Syrian Observatory for Human Rights.

Iran is being hit by a "war" on its economy, according to officials facing tightened U.S. sanctions and renewed Israeli threats of imminent military action over Tehran's nuclear activities.

"This is war," Ayatollah Ahmad Janati, the hardline chief of Iran's influential Guardians Council, said as he led Friday prayers in Tehran.

A U.N. General Assembly resolution condemning Syria's use of heavy weapons and the Security Council's failure to act means the Syrian regime has lost legitimacy, the head of the opposition Syrian National Council said on Friday.

"This vote confirms that this regime lost its legitimacy and that the international community does not believe in its legitimacy anymore," Abdel Basset Sayda told a news conference in Arbil, the capital of Iraq's autonomous Kurdistan region, region referring to a resolution passed earlier on Friday.

Russia expressed serious concern Friday over attempts by Syrian rebels to gain control of Aleppo and condemned foreign nations for providing the armed opposition with military supplies.

The foreign ministry said the latest evidence from Syria's second city showed that "illegal armed formations" were trying to make Aleppo into a base for future attacks on Syrian President Bashar Assad's troops.

The U.N. General Assembly overwhelmingly passed a resolution Friday criticizing the Security Council's failure to act on the Syria conflict, which U.N. leader Ban Ki-moon said has become a "proxy war".

The resolution, which condemned President Bashar Assad's use of "heavy weapons" in his battle against the rebellion against his rule, was passed by 133 votes with 12 countries against and 31 abstaining.

U.N. leader Ban Ki-moon said Friday that the Syria conflict has become a "proxy war" and that the international powers must overcome rivalries to end the violence.

Evoking the U.N.'s failure in the Srebenica massacre in Bosnia, Ban warned the divided U.N. Security Council that "the immediate interests of the Syrian people must be paramount over any larger rivalries of influence."

Another Syrian brigadier general has crossed the border into Turkey to join the ranks of opposition fighters, bringing the total number of rebel generals in Turkey to 29, a diplomat said Friday.

The general was accompanied by his family, he told Agence France Presse.

Protesters in Aleppo took to the streets Friday to demand death for Syrian President Bashar Assad even as violence raged there and 90 people were killed nationwide.

The Local Coordination Committees, the main activist group spurring protests on the ground, said regime forces shot dead at least 90 people across the country, among them 66 in Hama that witnessed a “massacre” in its al-Arbaeen neighborhood.

Palestinian President Mahmoud Abbas strongly condemned on Friday the "heinous" attack on a Palestinian refugee camp in the Syrian capital, which killed 21 civilians.

"We condemn the heinous crime committed against our people in the Yarmouk refugee camp in Damascus, in which dozens of unarmed civilians were killed and wounded," his office said.

A senior Egyptian Coptic bishop said on Friday attacks on Christians are on the rise and criticized the inclusion of only one Copt in Islamist President Mohammed Morsi's government.

"The general climate is turning against Christians," said Bishop Morcos. "Assaults on Christians have increased. It's not just a matter of having one ministry," he told Agence France Presse.