Russia helps Syria launch strikes after rebel fighters seize control of major city of Aleppo

Over the weekend, rebel fighters in Syria appeared to take control of the major city of Aleppo, after a battle with government troops. The Syrian regime and its ally, Russia, have responded with deadly airstrikes. The Syrian civil war began in 2011 but it has been largely in a stalemate for years. CBS News' Holly Williams has the latest from the Middle East.