Syrian forces pounded a neighbourhood of the eastern city of Deir Ezzor with mortar fire on Tuesday, killing 10 civilians including a young girl, a monitoring group said.
The attack, which targeted the city's Al-Jbaible neighbourhood, came a day after 12 people, including three children, were killed in a car bomb blast in Deir Ezzor's Al-Joura neighbourhood, the Syrian Observatory for Human Rights said.
Activists in Deir Ezzor said the car used in Monday's bombing belonged to a man who was detained several months ago by military intelligence, adding that the vehicle had been confiscated by authorities, and that the explosion was "the regime's doing."
The allegations could not immediately be verified due to severe restrictions on the media in Syria.
Thousands of people gathered in Deir Ezzor on Monday night to protest the blast, chanting slogans against President Bashar al-Assad such as "Traitor, traitor, O Bashar," the activists said.
Regime forces also on Tuesday shelled the town of Hreitan in the northern province of Aleppo, the Britain-based Observatory said, adding that regular soldiers clashed with armed rebels at the entrance to the town, leading to "heavy losses among regime troops."
The shelling "destroyed a large number of houses ... and forced residents to flee," said the Local Coordination Committees, which spearheads protests against the regime.
Tuesday's violence came as Syria's main opposition bloc accused the regime of escalating attacks across the country in an attempt to wipe out the anti-regime rebellion.
"Amid Arab and international weakness and hesitation, and taking advantage of the protection afforded by the UN Security Council, the Syrian regime is escalating its policy of fear and terror against the Syrian people," the Syrian National Council (SNC) said in a late Monday statement.
It said the regime was using helicopters, artillery and tanks, while deploying "thousands of troops" to besiege the central city of Homs, where rebels control several districts.
The regime is "denying residents access to electricity, food, medicine, medical treatment and even bread," the SNC said, noting that the areas of Khaldiyeh, Jourat al-Shiah, Qusayr and Al-Qarabees were particularly affected by the latest escalation, as was the town of Al-Heffa in coastal Latakia.
Regime forces have "turned schools into prisons and bases...and told residents to flee their homes, in an effort to empty Homs completely of its residents," the SNC said.
The Syrian Observatory for Human Rights said nationwide violence cost the lives of at least 111 people on Monday, including 79 civilians.
Reports of high daily death tolls are becoming the norm in Syria where over 14,000 people have been killed since an anti-regime revolt erupted in March 2011, according to the Observatory.