By Dominic Evans and Parisa Hafezi BEIRUT/ANKARA (Reuters) - Islamic State fighters have seized villages close to the northern Syrian city of Aleppo from rival insurgents, a monitoring group said on Friday, despite a Russian air-and-sea campaign that Moscow says has targeted the militant group. Iran's elite Revolutionary Guard Corps said separately one of its generals had been killed late on Thursday near Aleppo, once Syria's most populous city. Iran, like Russia an ally of President Bashar al-Assad, says it has advisers in the country.