AFP - Regime forces launched a new blitz on the Syrian city of Homs on Thursday, killing more than 50 people, activists said, as the UN weighed a joint mission with the Arab League to end the violence.

Shelling erupted at daybreak, killing 53 civilians in the besieged central city and burning several bodies beyond recognition, the Syrian Observatory for Human Rights said.

Government troops trying to crush opponents of President Bashar al-Assad have killed at least 400 people in a relentless six-day onslaught on Homs, activists say.