United Nations: UN Secretary-General Ban Ki-moon has voiced deep concern at the "increased militarisation of the conflict and the potential for sectarian atrocities" in Syria, Xinhua reported.
"Syria began the year in conflict, and ends the year in war," the secretary-general said at his year-end press conference Wednesday.
"Day by day, the death toll has climbed. Month by month, the regional spillover has grown."
"The Syrian opposition is coming together. This critical," Ban said. "I am deeply concerned about the increased militarisation of the conflict and the potential for sectarian atrocities."
Ban said that earlier this month, deputy UN secretary-general Jan Eliasson visited Lebanon, "where government officials and others voiced serious concern about the worsening regional implications".
Ban has visited Syrian refugees in Jordan and Turkey to see the situation for himself.
"They expressed grief at the decision of their cities and villages, and fear and anger at the growing targeting of people because of their religious or ethnic identity," the secretary-general said.
Lebanon, together with Jordan and Turkey, is hosting a massive influx of Syrian refugees who fled their country.
"The exodus has reached more than 500,000 people," Ban said. "It will grow in number as fighting rages, and in intensity as winter takes hold."
"Neighbouring countries face a huge financial burden in sheltering and caring for them. The increasing peril faced by Palestinian refugees in Syria is another growing concern."
"I call on the international community to respond generously and urgently to the humanitarian appeal launched in Geneva. I am considering convening an international donor conference, in close coordination with key partners, early next year," he said.
In Geneva Wednesday, the UN launched the new Syria Humanitarian Assistance Response Plan and Syria Regional Response Plan to provide humanitarian assistance in and outside Syria for the first half of 2013.
The two plans altogether appealed for some $1.5 billion, with $519 million for an estimated four million people in Syria in need of urgent humanitarian assistance and $1 billion for up to one million Syrian refugees in Egypt, Jordan, Iraq, Lebanon and Turkey.
The secretary-general also urged the international community to "unite firmly behind the mediation efforts" of the joint special envoy of the UN and Arab League for Syria, Lakhdar Brahimi.
"Syria needs a peaceful, political solution that brings democratic change, while preserving the fabric of Syrian society and the peaceful coexistence of its communities," Ban said.