Reuters

Women display ink-stained thumbs and fingers painted in the colours of the Syrian flag during a march in Sana'a, to show solidarity with Syrian anti-government protesters.

Amman/Beirut - Syrian government artillery barrages killed dozens of civilians in Homs on Thursday, activists said, as President Bashar al-Assad, bolstered by Russian support, ignored appeals from world leaders to halt the carnage.

The United Nations secretary-general condemned the “appalling brutality” of the operation to stamp out the revolt against Assad, and Turkey's ambassador to the European Union warned of a slide into civil war that could inflame the region.

Diplomats from Western and Arab powers, lining up meetings that could mean some decisions soon, condemned Assad in strong language. But having ruled out military intervention, they were struggling to find a way to convince him to step down.

Syria's powerful ally Russia, meanwhile, said no one should interfere in the country's affairs.

In Homs, witnesses said makeshift hospitals were overflowing in besieged opposition areas with the dead and wounded from nearly a week of government bombardments and sniper fire.

Medical supplies and food were running out and, in the streets, some of the wounded had bled to death as it was too dangerous for rescuers to bring them to safety.

The Local Coordination Committees, an opposition group in Homs, put the death toll on Thursday alone as high as 110 by nightfall, though it remains impossible to verify such accounts:

“This number includes three families whose bodies were dug up from under the rubble of their homes, bodies brought to field hospitals and people who died their from their wounds today,” the group said in a statement sent to Reuters.

A Syrian doctor, struggling to treat the wounded at a field clinic in a mosque, delivered an emotional plea via YouTube video. Standing next to a bloody body on a table, the man, named only as Mohammed, said to the camera, and to the outside world:

“We appeal to the international community to help us transport the wounded. We wait for them here to die in mosques. I appeal to the United Nations and to international humanitarian organisations to stop the rockets from being fired on us.”

Concern was growing in foreign capitals over the plight of civilians.

The United States said it was considering ways to get food and medicine to them - a move that would deepen international involvement in a conflict which has wide geopolitical dimensions and has caused division between world powers.

“I fear that the appalling brutality we are witnessing in Homs, with heavy weapons firing into civilian neighbourhoods, is a grim harbinger of things to come,” UN chief Ban Ki-moon said after briefing the Security Council in New York on Wednesday.

Neighbouring Turkey, which once saw Assad as an ally but now wants him out, has said it can no longer stand by and watch. It wants to host an international meeting to agree ways to end the killing and provide aid.

Foreign ministers of the Arab League, which the UN’s Ban said was planning to revive an observer mission it suspended last month, are due to meet in Cairo on Sunday.

But in Moscow, Russian foreign ministry spokesperson Alexander Lukashevich reiterated that Kremlin view that though the bloodshed was regretable, a solution was a matter for Syria.

“There is an internal conflict, the word revolution is not being used - it is a not a revolutionary situation, believe me,” he said.

Russia and China, which let the United Nations support the air campaign that helped oust Muammar Gaddafi in Libya, provoked strong condemnation from the United States, European powers and Arab governments when they vetoed a resolution in the Security Council last week that called on Assad to step down.

Moscow, for whom Syria is a buyer of arms and host to a Soviet-era naval base, wants to counter US influence and maintain its traditional role in the Middle East.

For both Russia and China, Syria is also a test case for efforts to resist international encroachment on sovereign governments' freedom to deal with rebels as they see fit.

Lukashevich's comments followed remarks on Wednesday from Russian Prime Minister Vladimir Putin, who drew clear lines on a foreign role in the crisis.

“Help them, advise them, limit, for instance, their ability to use weapons but not interfere under any circumstances,” Putin said. - Reuters