Syrian activists say a government air strike has killed at least 18 people in a residential area in the country's north, while a car bomb has killed five people in a Damascus suburb.
The activists said women and children were among those killed in Monday's air strike in the town of al-Bab. They said other people were feared dead under the rubble of damaged homes.
The activists said the car bombing in the Damascus district of Jaramana also wounded at least 27 people.
UN-Arab League Envoy: 'A terrible weight'
On the diplomatic front, international peace envoy Lakhdar Brahimi said in an interview with the BBC that he faces a nearly impossible task in trying to resolve Syria's 18-month conflict between President Bashar al-Assad's government and rebels fighting to end his 11-year autocratic rule.
The Algerian diplomat said he does not yet see any ways around the barriers that blocked the efforts of his predecessor, Kofi Annan, but that he will continue trying.
Brahimi says he realizes the difficulty of his task, and that success "should be possible," but that the lack of international action as people in Syria continue dying "is a terrible weight."
Annan quit last month, complaining that he could not fulfill his mission due to international divisions on Syria and escalating attacks by both Syrian government and rebel forces.
French Foreign Minister Laurent Fabius said any use of chemical or biological weapons by Assad's forces against the Syrian opposition will trigger a "massive response" from Western powers who want him to step aside.
Fabius said in broadcast interviews Monday there is broad agreement about such a response, calling chemical weapons "a very big danger."
ICRC lobbies for access
Meanwhile, the new head of the International Committee of the Red Cross was traveling to Syria for a meeting with Assad to seek government permission for humanitarian access to civilians caught up in the conflict.
In a statement released ahead of his trip, Peter Maurer said it is of "utmost importance" for the Red Cross and its local partner, the Syrian Arab Red Crescent, to significantly scale up the humanitarian response at a time when more civilians are being "exposed to extreme violence." He said an adequate response is required to keep pace with humanitarian needs that have been growing "exponentially."