I sing in a choir <a href=" http://www.fotostudio5.net/clonidine-tablet-to-patch-conversion.pdf ">what is clonidine hydrochloride used to treat</a> Russia has been Assad's most powerful backer during the civil war that has killed more than 100,000 people since 2011, delivering arms and - with China - blocking three Security Council resolutions meant to pressure Assad.