The Wall Street Journal reports: A tenuous cease-fire in Syria unraveled further over the past few days, with rebel groups that signed on joining the al Qaeda-linked Nusra Front in a new offensive against regime forces near the northern city of Aleppo.

Amid the offensive in its fourth day on Monday, Nusra supporters were mourning a top figure in the group and nearly two dozen of his associates killed in airstrikes in northwestern Idlib province on Sunday.

Nusra supporters blamed the airstrike on the U.S., which has previously targeted the group’s fighters in Idlib, its stronghold.

A spokesman for the American-led coalition that is mainly battling Islamic State wouldn’t immediately confirm nor deny the allegation. Russia and the Syrian regime also conduct airstrikes on opponents in the area.

The truce has been imperiled by an escalation of regime airstrikes on rebel-held suburbs of the capital Damascus over the past week. Despite a rapidly rising toll of alleged violations, both sides appear reluctant to call off the agreement which has reduced violence and deaths after all.

“The cessation of hostilities agreement is about to take its last breath and effectively be declared finished,” Riad Hijab, an opposition leader, warned in a letter to United Nations Secretary General Ban Ki-moon on Friday. Mr. Hijab heads the main opposition delegation to the Geneva peace talks.

Continuing regime restrictions on humanitarian assistance to several besieged rebel-held areas around Damascus are further straining the shaky truce. Residents of one such town, Madaya, said a sick teenager died Monday because of lack of medical care.

Regime airstrikes on a rebel-held community near Damascus on Thursday killed 33 people, almost half of them children, according to a tally by local emergency responders. [Continue reading…]