UNITED NATIONS: Syria's war has reached “unprecedented levels of horror”, UN envoy Lakhdar Brahimi said after dozens of men were found slaughtered, just ahead of a donors' conference for the devastated country.

Brahimi told the divided UN Security Council Tuesday it had to act now to halt the carnage epitomized by the at least 78 young men, each killed with a single bullet and dumped in a river in the battlefront city of Aleppo.

More bodies were still to be retrieved from the water.

Syrian rebels blamed President Bashar al Assad's government for the killings, but state media said a religious militant opposition faction was to blame.

Syria “is breaking up before everyone's eyes,” Brahimi told the council's 15 ambassadors.

“Only the international community can help, and first and foremost the Security Council.”

Twenty-two months of conflict have now left well over 60,000 dead, according to the United Nations, which is seeking $1.5 billion in humanitarian funding for beleaguered Syrians at a conference in Kuwait on Wednesday.

“The tragedy does not have an end,” Brahimi said.

The Assad government's legitimacy has been “irreparably damaged,” Brahimi said, warning, however, that it could still cling to power.

Assad's forces had become more repressive, the former Algerian foreign minister was quoted as telling the closed meeting.

Both the state and the rebel opposition were committing “equally atrocious crimes”, he added.

He also warned of the conflict spilling over into neighboring countries.

“None of the neighbors is immune to the fallout consequences of the conflict.”

“Syria is being destroyed bit by bit,” Brahimi told reporters after briefing the Security Council.

“And in destroying Syria, the region is being pushed into a situation that is extremely bad and extremely important for the entire world,” he added.

“That is why I believe the Security Council simply cannot continue to say 'we are (in) disagreement, therefore, let's wait for better times'. I think they have got to grapple with this problem now.”

But US ambassador Susan Rice said “the same issues that have stymied the council to date remain unresolved, so there is no obvious way forward.”

The Security Council has been paralysed on Syria for more than a year.

Russia and China have vetoed three Western-drafted resolutions which would simply have threatened sanctions.

Russia accuses the West of seeking regime change through force and insists it cannot make Assad stand down. The United States and its allies back the opposition stance that there can be no talks with Assad.

In Aleppo, rebel fighter Abu Seif said 78 bodies had been retrieved from the QuweiqRiver and that 30 more were still in the water but could not be reached because of the threat of Assad snipers.

Hundreds of distressed people watched as muddied corpses were dredged from the Quweiq.

“The regime threw them into the river so that they would arrive in an area under our control, so the people would think we killed them,” Abu Seif said.

Volunteers heaped bodies on a truck, which took them to a school, where they were laid out and covered.

“We do not know who they are,” one volunteer said. “They were not carrying papers.”

A government security official blamed “terrorists” – the regime term for the rebels – for the carnage. The official SANA news agency said the terrorist Al-Nusra Front was responsible.

Al-Nusra, which has gained notoriety for its suicide bombings, has become a key fighting force, leading rebel attacks throughout the embattled country.

Its suspected affiliation to the Al Qaeda offshoot in Iraq has seen it added to the US list of terrorist organisations.

“The suffering of men, women and children has reached unprecedented levels across the country,” said a statement from the International Committee of the Red Cross.

With no end to the fighting in sight, their plight would get worse, it added.

January's harsh weather conditions had “not only deepened the misery of displaced people” but made it harder for aid convoys to get through to them, the statement said.

On the eve of the donors' conference in Kuwait, US President Barack Obama announced an extra $155 million to aid refugees fleeing what he said was “barbarism” propagated by Assad's government.

Charity organisations pledged $182 million  for Syrians. Kuwait Emir Sheikh Sabah al-Ahmad al-Sabah opened the international donors conference with a pledge of $300 million in aid for Syrians affected by the 22-month conflict.