The ground-attack aircraft struck a building in the Sunni Muslim city of al-Bab, northeast of Aleppo, causing the building to collapse, killing at least 35 people, witnesses said.
The overall death toll in al-Bab and Aleppo, Syria's largest city, was more than 60 Monday and more than 250 across the country, the activist Local Coordination Committees said.
The rebel Free Syrian Army captured al-Bab in July and the Assad regime has been shelling it ever since, activists say.
In Damascus, a bomb hooked to a taxi blew up Monday in a religiously mixed district on the southeast edge of the city, killing at least five people and wounding nearly two dozen, state media and opposition activists said.
The state-run Syrian Arab News Agency said some of the dead and wounded were women and children.
At least 12 people were killed by a car bomb in the same area last week.
Syrian security forces killed 16 people execution-style in the northern Damascus neighborhood of Qabun, al-Jazeera reported, citing activists.
In besieged Homs, 100 miles north of Damascus, fighters seeking President Bashar Assad's ouster said they recaptured a national hospital. Rebels posted a video online that showed a tunnel where explosives had been planted underneath the hospital. The explosives were detonated before armed rebel fighters recaptured it.
As the war persists, veteran U.N. envoy and adviser Lakhdar Brahimi, who succeeded former U.N. Secretary-General and Nobel Peace laureate Kofi Annan as special U.N.-Arab League envoy to Syria, told the BBC he was "scared" of the task ahead.
He said Annan, who resigned as special envoy Aug. 2, had come up against a "brick wall," including an "intransigent" Syrian regime, escalating violence by opposition forces and what Annan described as a paralyzed U.N. Security Council.
"I'm standing in front of that same wall," Brahimi, a 78-year-old former Algerian diplomat, told the BBC. "I don't see a crack."
Speaking in New York after meetings with Security Council members, including U.S. Ambassador Susan Rice, Brahimi said he was "coming into this job with my eyes open, and no illusions."
"I know how difficult it is -- how nearly impossible. I can't say impossible -- nearly impossible," said the diplomat, who has worked for the United Nations in other trouble spots, including Afghanistan and Iraq.
But he said a thread of hope included Syrians' national identity, which he said he felt was more important than sectarian divisions.
"I have been going to Syria for 50 years or more and have seen this mosaic of communities ... who put their Syria identity first," Brahimi said. "I refuse to believe Syrians will forget that, go back to narrow identities, and find it indispensable to kill their neighbor."
When he formally accepted his assignment, Brahimi told Secretary General Ban Ki-moon he was "honored, flattered, humbled, scared."
He explained to the BBC Monday he was "scared of the weight of responsibility."
"People are already saying, 'People are dying and what are you doing to help?'" he said. "We are not doing much."
The United Nations also reported that more than 100,000 refugees fled Syria to neighboring countries in August, the largest monthly total in the 18-month crisis, bringing the total of registered or awaiting-registration refugees to 253,300, or 1 percent of Syria's total population.
Peter Maurer, president of the International Committee of the Red Cross, met Tuesday with President Bashar Assad to obtain better access to civilians involved in the war, an agency spokesman said. Medics are treating the injured in with limited supplies in makeshift clinics, often without electricity, CNN reported Tuesday.
"Its very hard to access people in need, " said Red Cross spokeswoman Cecelia Goin. "The humanitarian situation is deteriorating fast."