After bombarding Homs for the last 13 days, Syrian government forces have now launched an offensive against the country's fourth largest city of Hama.

But it is Homs which has so far borne the brunt of President Bashar al-Assad's crackdown. Activists say six more people were killed on Tuesday, bringing the estimated toll above 400 since the assault there began.

The UN believes that the recent vetoing by Russia and China of a Security Council resolution has encouraged Assad's regime to intensify its attacks on civilians..