Syrian forces bombarded opposition-held neighbourhoods of the city of Homs with rocket and mortar fire on Thursday, activists said, as divided world powers struggled to find a way to end the violence.
The United Nations chief condemned the ferocity of the government assault on the heart of a revolt against President Bashar al-Assad that broke out nearly a year ago and is getting bloodier by the day.
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, U.N. Secretary General Ban Ki-moon said after briefing the Security Council in New York.
Activists and residents report hundreds of people killed over the last week as Assad's forces try stamp out opposition in Homs and as Thursday dawned, rocket and mortar fire rained down again on Baba Amro, Khalidiya and other districts. Armoured government reinforcements also poured into the eastern city.
A Syrian doctor, struggling to treat the wounded at a field clinic in a mosque, launched an emotional video appeal over the Internet for the world to stop the killing and send aid.
Concern was growing over the plight of civilians and 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 foreign powers.
Turkish Foreign Minister Ahmet Davutoglu said before flying to Washington for talks on Syria that Turkey, which once saw Assad as an ally but now wants him out, could no longer stand by and watch. Turkey wanted to host an international meeting to agree ways to end the killing and provide aid, he said.
It is not enough being an observer, he told Reuters, though Russia and China have warned against interference.
Foreign ministers of the Arab League, which the U.N.'s Ban said was planning to revive an observer mission it suspended last month, are due to meet in Cairo on Sunday. They may want to hear other governments' ideas by then.
China, cool to Western lobbying for international involvement, nonetheless reported its first formal contact with a Syrian opposition figure who visited Beijing last week.
HOMS UNDER FIRE
The Syrian Revolution Coordinating Commission said at least 30 civilians in Homs were killed in bombardments on Thursday morning on mainly Sunni Muslim neighbourhoods that have been the focus of attacks by the government forces led largely by members of Assad's Alawite religious minority.
Such sectarian divisions have been coming to the surface as killings have increased on either side of the conflict.
The main street in Baba Amro was strewn with rubble and at least one house was destroyed, according to YouTube footage broadcast by activists from the district who said troops had used anti-aircraft cannon to demolish the building.
The video showed a youth putting two bodies wrapped in blankets in a truck. What appeared to be body parts were shown inside the house.
Hussein Nader, an activist in Baba Amro, told Reuters: Silence reigns for four to five minutes, then another barrage of tank fire or rockets or mortar rounds comes in.
Whole houses have come down and we do not know how many more have been killed. They are not advancing and it seems that they are content by continuing to shell Baba Amro until every inhabitant is killed.
A doctor, his name given only as Mohammed, broadcast a cry for help on YouTube from his makeshift surgery in a mosque.
Standing next to a bloody body on a table, he said: 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.
The Syrian Human Rights Organisation (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 toll in Syria since last March at more than 5,000.
Activists said neighbourhoods of Homs remained without electricity and water and basic supplies were running low.
There was no comment from the Syrian authorities, who have placed tight restrictions on access to the country and it was not possible to verify the reports of local activists.
Mazen Adi, a prominent Syrian opposition figure in Paris, said rebels loosely organised under the Free Syrian Army were fighting back and staging hit-and-run guerrilla attacks against government forces in Homs.
The regime cannot keep tanks for long inside opposition neighbourhoods because they will be ambushed, he said.
The role of the FSA, largely made up of soldiers who have defected from the government forces, highlighted the slide in the uprising against the Assad family's 42-year dynastic rule from civilian demonstrations to armed insurgency over the past few months. The Assad government contends it is fighting foreign -backed armed terrorists.
Syria's position at the heart of the Middle East, allied to Iran and home to a volatile religious and ethnic mix, means Assad's international opponents have ruled out the kind of military action they took against Libya's Muammar Gaddafi.
Russia and China, which let the United Nations support the air campaign 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 U.S. 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.
Campaigning for next month's presidential election that he is certain to win, Prime Minister Vladimir Putin, said: Help them, advise them, limit, for instance, their ability to use weapons but not interfere under any circumstances.
Russian President Dmitry Medvedev told Turkish Prime Minister Tayyip Erdogan in a phone conversation that the search for a solution should continue but that foreign interference was not an option.
French President Nicolas Sarkozy also spoke to Medvedev on Wednesday night and said that despite their differences, it was necessary to maintain pressure on Assad's government so that the repression ended.
(Sarkozy) asked that Russia give its total support to the Arab League to convince Assad to step aside, to avoid a civil war that threatened Syria and the stability of the region and to allow an orderly political transition, Sarkozy's office said.
The U.N.'s Ban said it was more urgent than ever to find common ground. In an implicit criticism of the Assad government, he said: Such violence is unacceptable before humanity ... We have heard too many broken promises, even within the past 24 hours.
In Washington, officials said the United States planned to meet soon with its allies to discuss ways to halt the violence and provide humanitarian aid to civilians under attack.
White House spokesman Jay Carney said the talks, which would include the opposition Syrian National Council, were aimed at helping the process move toward a peaceful, political transition, democratic transition in Syria.
Any international move to bring in humanitarian aid could open a dangerous and complicated new chapter in the crisis, with air drops seen as expensive and ineffective and any land routes open to attack from Syrian forces. But the White House stressed it was not actively considering military intervention.
(Additional reporting by Simon Cameron-Moore and Tulay Karadeniz in Ankara, Steve Gutterman in Moscow, Erika Solomon in Beirut, John Irish in Paris, Yasmine Saleh and Ayman Samir in Cairo and Alister Bull, Matt Spetalnick and Andrew Quinn in Washington; Writing by Angus MacSwan in Beirut; Editing by Alastair Macdonald)