Reuters reports: Syrian forces bombarded opposition-held neighborhoods 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 Homs, 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 neighborhoods, is a grim harbinger of things to come,” U.N. Secretary General Ban Ki-moon told reporters after briefing the Security Council.

Activists and residents report hundreds of people killed over the last week as Assad’s forces try stamp out opposition in Homs, and as dawn broke on Thursday, rocket and mortar fire rained down again on Baba Amro, Khalidiya and other districts. Armored reinforcements also poured into the eastern city.

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.”