Regime forces killed at least 28 civilians with heavy gunfire in the central city of Hama on Monday, the Syrian Observatory for Human Rights said.
The Britain-based watchdog, which had earlier put the number of dead at 25, said the victims were shot by regime forces in and around the city’s Arbaeen neighbourhood.
It said five charred bodies were also found in the neighbourhood on Monday. The circumstances surrounding their deaths were unclear.
Videos posted by activists on YouTube showed the area being shelled with mortars, sending up plumes of white smoke.
The watchdog said another civilian was killed overnight in Damascus province amid clashes between opposition and government forces.
It added that five soldiers were also killed in clashes in Hama province and and in Daraa province, south of Damascus.
In Deir Ezzor, in northeast Syria, the Observatory reported raids and arrests by government forces as well as heavy shooting in the town of Al-Quriyah.
Al-Jura district of Deir Ezzor was besieged by pro-regime militia, it added.
The UN observers visited several rebel suburbs near the capital and were met by thousands of protesters demanding the collapse of the regime.
Amateur video posted by activists on YouTube showed four of the unarmed observers in blue helmets walking in Douma, a northern suburb of Damascus, surrounded by a huge crowd waving Syria independence flags.
‘The people demand the fall of the regime,’ some chanted while others called for the arming of the rebel Free Syrian Army.
Monitors also visited the town of Zabadani, 50 kilometres northwest of the capital, where regime forces and rebel fighters have clashed repeatedly in past months.
Fares Mohamed, an activist in Zabadani, said the observers’ visit lasted barely a half hour.
‘They refused to head to a location less than a kilometre from the town to see tanks hidden by the regime,’ said Mohamed, who was reached via Skype.
Two members of the observer advance team on Sunday set up base in the central city of Homs, scene of some of the fiercest fighting between government troops and rebels since the outbreak of the 13-month revolt against president Bashar al-Assad’s regime.
The official state news agency SANA said the observers toured the battered city’s Al-Waer neighbourhood on Monday.
UN leader Ban Ki-moon has decided that the deployment of 300 ceasefire monitors in Syria can start next week, a UN spokesman said on Monday.
Following a UN Security Council resolution that allowed the mission, Ban was left to make an ‘assessment’ as to whether it was safe for the monitors to go. ‘The decision has been taken’ and the monitors should start arriving next week deputy UN spokesman Eduardo del Buey said.
Activists have been sceptical of the UN mission, saying the regime was simply buying time and was not committed to the ceasefire plan.
Abu Omar, an activist in Damascus, said the observers were playing by the regime’s rules by coordinating all their movements exclusively with the authorities.
‘They are not coordinating with us and by not doing so, their mission does no good to the Syrian people,’ he said. ‘Their mission is a failure because they are not working with people on the ground.’
Despite a lull in the fighting in regions visited by the observers, the violence has continued unabated in other areas, activists say.
One civilian was killed overnight in Damascus province amid clashes between opposition and government forces, the Observatory said.