BEIRUT (AP) -- After a brief morning lull, Syrian government warplanes launched fresh airstrikes Friday targeting rebel-held parts of Aleppo, raising fears of more casualties after days of carnage that propelled the contested northern city once again as a main battlefield in Syria's devastating civil war.
The airstrikes shattered the lull that had engulfed Aleppo since dawn hours and prompted religious leaders to suspend Friday prayer sermons in the city mosques, according to activists from the Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees.
The Observatory reported one person was killed in the strikes while the LCC said three people died and several were wounded.
The carnage in Aleppo — a city contested since the summer of 2012 when opposition fighters stormed it and took over several neighborhoods — was particularly bad on Wednesday and Thursday, when airstrikes and artillery killed more than 60 people, including dozens at a hospital in a rebel-held neighborhood.
Aid agencies warned that Aleppo is on the brink of a humanitarian disaster with the collapse of a two-month cease-fire and stalled peace talks in Switzerland.
In Geneva, the U.N. High Commissioner for Human Rights said the latest reports of civilian deaths in Syria revealed a "monstrous disregard for civilian lives by all parties to the conflict."
In a statement released Friday, Zeid Ra'ad Al Hussein urged all sides to step back from a return to an all-out war.
The U.N. official said "the violence is soaring back to the levels we saw prior to the cessation of hostilities" in late February. He added that targeting medical facilities and markets could "amount to war crimes."
According to the Observatory, airstrikes and shelling in Aleppo killed 202 civilians in the past week — 123 in rebel-held parts of the city and 71 and government-held areas. It said the dead included 31 children on both sides.
The Religious Council of Aleppo, a body that runs religious affairs in rebel-held parts of Aleppo province, suspended Friday prayers at the city's mosques, saying there were fears of more airstrikes by Russian and government warplanes.
"The religious council calls upon, for the first time, all those in charge of mosques to suspend the Friday prayers," said the council in a statement posted online. "The heart of the believers is aching ... but preserving lives is an important religious duty."