geneva unite nations condemn coordinate series attack myanmar security force friday call side crisis northern state rakhine refrain violence least 21 insurgents 11 members security force kill trouble rakhine state friday militants stag major coordinate attack 24 police post army base military say statement issue u.n. resident coordinator myanmar renata lok-dessallien read geneva news brief urge party refrain violence protect civilians restore order deeply concern security situation rakhine state add u.n. condemn attack myanmar security force call calm