AMMAN/BEIRUT - Syrian government artillery barrages killed dozens of civilians in Homs on Thursday, activists said, as President Bashar 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.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 organizations to stop the rockets from being fired on us."The Syrian Human Rights Organization (Sawasiah) said this week's assault on Homs had killed at least 300 civilians and wounded 1,000, not counting Thursday's toll. International officials have estimated the overall death count in Syria since last March at more than 5,000.UN, Arab League seeking to renew monitors mission Arab foreign ministers will discuss a proposal next week to send a joint UN-Arab mission to Syria, a senior Arab League official said on Thursday, after a solely Arab team failed to end Assad's crackdown on protests.Ministers will meet in Cairo on Sunday to consider whether to extend or scrap an observer mission sent to Syria in December but which was criticized by Syria's opposition, faced internal dissent and retreated to hotels for safety as violence surged.One Arab diplomat said the ministerial meeting could also issue a statement on a decision by Russia and China to veto a UN Security Council resolution that was based on an Arab peace plan and which had the backing of Western powers. The Russian and Chinese veto drew Arab criticism.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.