Syrian regime warplanes unleashed relentless pre-dawn air raids Tuesday on rebel positions around Maaret al-Numan, a strategic northern town captured by insurgents last week, activists said.
The raids were the "most violent" since the rebels took full control of the town in the province of Idlib last Wednesday, Rami Abdel Rahman, the head of the Syrian Observatory for Human Rights, told AFP.
Maaret al-Numan is strategically located in the northwest on the highway linking Damascus to the embattled city of Aleppo.
Large swathes of Idlib and Aleppo as well as the countryside abutting the Turkish border have fallen into rebel hands in recent months, setting regime forces on the back foot in the country's north.
The warplanes dropped bombs in a bid to break a rebel blockade of the highway, which is preventing army reinforcements from reaching Aleppo, theatre of intense fighting between rebels and the army for the past three months.
"The bombing is targeting the villages of Hish, Maarshamsha, Maarshamrin, Talmans and Deir al-Gharbi in the vicinity of Maaret al-Numan," the Observatory said, adding that rebels were responding with anti-aircraft guns.
The loyalist army is trying to regroup its forces but is failing to get its reinforcements through, said Abdel Rahman.
While it tries to subdue the insurgency in the north, the army is also engaged in an attempt to put down rebels in the Eastern Ghuta area of countryside on the outskirts of the capital.
On Tuesday, the army pounded the eastern Damascus district of Jobar, home to strong anti-regime sentiment, the Observatory said.
The army meanwhile clashed with rebels in the town of Ain Tarma, also east of Damascus, and pounded the nearby town of Douma, the activists added.
The clashes and bombings come after another day of violence across Syria which left at least 151 people dead -- 78 civilians, 46 soldiers and 27 rebels, according to the Observatory.
The Observatory also said Tuesday it had managed to verify that most of the 28 corpses found near Damascus on Sunday were members of the regime's forces, while the rest were rebels.
"The 28 were killed in fighting around the capital in recent weeks," said Abdel Rahman.
The conflict in Syria, which entered its 20th month on Monday, started as peaceful protests for reform in the wake of the Arab Spring, but morphed into an armed insurgency when demonstrations were brutally crushed.
The conflict has so far left more than 33,000 people dead, according to figures from the Observatory.