French President Francois Hollande on Saturday urged the U.N. Security Council to rapidly intervene in the Syria conflict to pre-empt an all-out civil war.

"The role of the countries of the Security Council is to intervene as quickly as possible," he said, specifically addressing Damascus allies Russia and China and warning that failure to do so would mean "chaos and civil war."

More than 20,000 people have been killed in Syria since the start of an anti-regime revolt in March 2011, the Syrian Observatory for Human Rights said on Saturday.

"At least 20,028 people, among them 13,978 civilians and rebels, 968 army defectors and 5,082 members of the regime forces have been killed since the start of the revolt on March 15 of last year," Rami Abdel Rahman, director of the Britain-based Observatory, told Agence France Presse by phone.

A five-day Saudi fundraising campaign to support the people in Syria has raised more than $72.33 million, the kingdom's Interior Minister Prince Ahmed bin Abdul Aziz was quoted as saying Saturday.

The campaign, launched on Monday, received donations worth 271.245 million riyals ($72.33 million), the state news agency SPA reported quoting Prince Ahmed.

Russia said Saturday it would not cooperate with a new round of European Union sanctions against Syria and would not consent to inspections of ships flying the Russian flag.

"We do not plan to take any part in measures carrying out European Union decisions directed against Syria," foreign ministry spokesman Alexander Lukashevich was quoted as saying in a statement.

Russia warned Saturday that a "tragedy" was looming in Syria's second city of Aleppo but said it was unrealistic to expect the government would stand by when armed rebels were occupying major cities.

"We are persuading the government that they need to make some first gestures," Foreign Minister Sergei Lavrov told a news conference alongside his Japanese counterpart.

Two Italian technicians, who worked as subcontractors in Syria for Italian energy group Ansaldo, were released late on Friday after going missing for a week, the official SANA news agency said.

"During operations to cleanse some (rebel) areas in the province of Damascus, Syrian troops managed to liberate the two Italian technicians, who were kidnapped by an armed terrorist group," SANA said.

Syrian rebels staved off a fightback by regime forces in Aleppo on Saturday amid growing concern about the risks of reprisals against civilians in the country's commercial capital.

After massing for two days, troops backed by tanks and helicopter gunships moved on southwestern Aleppo where rebels concentrated their forces when they seized much of the northern city on July 20.

Turkey this week cranked up its already-heated rhetoric against Kurdish militants in northern Syria, saying it would not hesitate to go after PKK fighters, just as it has in northern Iraq.

Analysts warn such a move would be dangerous for Turkey and further complicate Syria's deadly conflict and the volatile regional situation.

Prime Minister Najib Miqati vowed on Saturday not to become a stumbling block to the formation of an “exceptional” government that requires foremost consensus among the Lebanese.

In an interview with pan-Arab daily al-Hayat in London, Miqati said: “I hold onto the success of the government at all levels despite all the hurdles and obstacles facing us … At the same time everyone knows that I don’t hold onto power but work to preserve the safety of Lebanon and the Lebanese.”

The United States said it was "very concerned" about a Syrian offensive in Aleppo, Syria, but rejected comparisons to Libya where NATO-led forces intervened last year to protect civilians.

"We are very concerned about the situation in Aleppo," White House spokesman Jay Carney said, condemning Syrian President Bashar Assad's "heinous, reprehensible" assault on Syrian civilians.