The Associated Press reports: At least 1,600 people were killed last week in Syria in the deadliest seven days since the uprising against President Bashar Assad began in March 2011, the U.N. children’s fund UNICEF said Sunday.

The civil war witnessed a major turning point in August when Assad’s forces began widely using air power for the first time to crush the revolt. The fighting also reached Syria’s largest city, Aleppo, which had been relatively quiet for most of the 17-month-old revolt.

Last week, activists reported that between 300 and 600 people were killed in the Damascus suburb of Daraya during days of shelling and a killing spree by troops who stormed the town after heavy fighting.

Over the past week, activists had been reporting daily death tolls for the entire country averaging 100-250, attributed in part to the increasingly heavy use of air power in different areas and daily rounds of shelling and clashes in Aleppo.