Bashar Assad regime loyalists are fighting rebels in Eastern Ghuta, outside Damascus.
They have also pounded Jobar, a stronghold in Damascus, and the towns of Harasta and Hammuriyeh.
Warplanes unleashed a wave of raids in Syria's north on Tuesday, “bidding to dislodge rebels whose seizure of a key highway has prevented reinforcements from reaching main battleground city Aleppo.” according to the report.
In other news, United Nations peace envoy to Syria, Lakhdar Brahimi, began a visit to Cairo, Egypt after issuing an appeal for a ceasefire during the upcoming Muslim holiday of Eid al-Adha.
Last week, Mr. Brahimi visited Turkey and Saudi Arabia, the two Sunni-led states that have assisted the Free Syrian Army (FSA) the most.
"Brahimi has appealed to the Iranian authorities to assist in achieving a ceasefire in Syria during the forthcoming Eid al-Adha, one of the holiest holidays celebrated by the Muslims around the world," his office told the AFP.
"He reiterated the call by UN Secretary General Ban Ki-moon for a ceasefire and a halt to the flow of arms to both sides. A ceasefire, he said, would help create an environment that would allow a political process to develop."
The escalation in Idlib province, on the Turkish border, came as a senior US official visited Ankara for talks. "We continue to consult with our partners in the region including Turkey on a variety of issues related to Syria," US embassy spokesman in Ankara T.J. Grubisha told AFP.
Tensions between Syria and Turkey have soared as Ankara and Damascus banned flights from each other's airspace after Ankara confiscated a cargo of radar equipment from a Syrian flight from Moscow last week.
The Syrian Observatory for Human Rights told that the pre-dawn air raids around Maaret al-Numan were the "most violent" since insurgents first seized the strategic Idlib province town earlier last week.
Fighter jets targeted the blockade of the highway to Aleppo. In Kafr Nabal, army shelling killed two children, 6 and 10, according to the Observatory.
Another five children under the age of six died along with two adults in shelling of homes at Mayadeen village in the eastern province of Deir Ezzor, said the Britain-based group.
2,300 of the 33,000 people killed in the conflict have been children, said the Observatory.