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.

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.

French Foreign Minister Laurent Fabius said any use of chemical or biological weapons by Mr. Assad's forces against the Syrian opposition will trigger a “massive response” from Western powers who want him to step aside.

Meanwhile, the new head of the International Committee of the Red Cross was traveling to Syria for a meeting with Mr. 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.”