Syrian security forces intensified their assault on opposition areas in the restive central city of Homs yesterday, as the US closed its embassy in Damascus citing security reasons and Britain recalled its top envoy.

The London-based Syrian Human Rights Observatory said at least 67 people had been killed nationwide yesterday, 54 of them in Homs. This added to a death toll that activists say had reached 200 in a three-day offensive launched the day before Russia and China vetoed a UN Security Council resolution calling for a political transition in Syria.

Yesterday’s shelling targeted most heavily the Bab Amr district, a stronghold of the Free Syrian army, security forces’ defectors who are the biggest challenge for the regime of Bashar al-Assad during the 11-month uprising.