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.

Turkey's army has begun staging drills at the Syrian border following warnings that it would follow Kurdish rebels across the frontier, the Anatolia news agency reported Friday.

Turkish tanks accompanied by armored personnel carriers and surface-to-air missile defenses are deployed at the Oncupinar crossing in southeastern Kilis province for the drills, the report said, adding that they would continue periodically.

Stepped up fighting in Syria could create a "gigantic outflow" of people on a previously unseen scale, the U.N.'s refugee commissioner said on Friday.

"We all have seen crises of this nature in different parts of the world, let's hope that this doesn't evolve into the kind of gigantic outflows we have witnessed in Afghanistan or Iraq," High Commissioner for Refugees Antonio Guterres told reporters in Geneva.

Around 500 people demonstrated in Jordan's capital for a protest dubbed "Press Freedom Friday" to denounce repression of the media and demand widespread reforms, Agence France Presse reported.

The protest began after Friday prayers at Amman's al-Husseini mosque, with a procession headed by a large banner announcing "Friday for freedom of the press."

Russia said Friday that Kofi Annan should be urgently replaced as envoy for Syria, appearing to pin the blame for his sudden resignation on the opposition to President Bashar Assad and the West.

Annan, the United Nations' and the Arab League's Syria envoy since February, resigned his post on Thursday blaming world powers for not giving him enough backing to his peace drive.

The rebel Free Syrian Army on Friday condemned and rejected responsibility for the execution of regime loyalists in the city of Aleppo after a video emerged of the reported killings.

"We strongly condemn this kind of irresponsible behavior and call on all revolutionary forces and the fighters on the ground to condemn such acts," said a statement issued by the FSA's joint command.