BEIRUT — Syrian attack helicopters and warplanes circled overhead in the country’s largest city of Aleppo, as fierce fighting continued in the former regime stronghold for a fourth day, and rebel fighters struggled to hold on to ground they gained earlier this week.
In Washington, Secretary of State Hillary Rodham Clinton sent “a clear message of support for the opposition,” while Syrian ally Russia warned Syrian President Bashar Assad against using chemical or biological weapons against a foreign attack.
