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.

Former premier Fouad Saniora, head of al-Mustaqbal parliamentary bloc, on Friday called on EU and U.N. officials to condemn the Lebanese government “in the strongest terms” over the recent deportation of 14 Syrians to their strife-torn country, voicing concerns that the step might be repeated in the future and stressing that the government will be held accountable.

Following separate talks with EU Ambassador Angelina Eichhorst and U.N. Special Coordinator for Lebanon Derek Plumbly, Saniora said: “Amid these circumstances, the timing of the operation is very suspicious, and this could be a precedent made by the Lebanese government following a request or pressures from the Syrian government to hand over these people, and thus it might be the first move and other people might be handed over.”

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.

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.

Syria’s Ambassador Ali Abdul Karim Ali lauded on Friday the Lebanese General Security’s deportation of 14 Syrians, describing the move as “reassuring.”

Following talks with former Premier Salim Hoss in Beirut’s Aisha Bakkar district, Ali said: “The General Security’s move came in line with international standards.”

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.

Britain's Foreign Secretary William Hague pledged greater support for Syria's rebel fighters on Friday, as the battle for the country's commercial capital Aleppo intensified.

"Given the scale of death and suffering and the failure so far of the diplomatic process we will, over the coming weeks, increase our practical but non-lethal support," Hague told BBC radio.

Three Russian amphibious assault ships carrying hundreds of armed navy personnel will briefly dock in a Moscow-leased Syrian port in the coming days, Russian news agencies reported on Friday.

The warships are currently conducting planned exercises in the Mediterranean Sea and will make a port call in Tartus to pick up fresh food and water supplies, the news agencies quoted an unnamed defense source as saying.

Iran on Friday blamed "interfering countries" for making Kofi Annan's mission fail in Syria, and implied it could now be among those taking "a more crucial role" in solving the conflict.

"It seems that interfering countries were not satisfied with the efforts made by Annan to halt the shipment of arms into Syria and (to put an end) to terrorist acts," foreign ministry spokesman Ramin Mehmanparast said during a visit to China, according to Iran's official IRNA news agency.