tell to stand down(the troops were stood down only when it was clear that no attack was forthcoming – боевую готовность отменили только тогда, когда выяснилось, что нападения не предвидитсяTaras)
being placed on high alert(англ. цитата приводится по кн.: Military Balance 2009. – London: International Institute for Strategic Studies, 2009 Alex_Odeychuk)
state of alert(Its press service told Interfax that 51,500 police including 2,000 interior troops had been on a state of alert since 1 December, as part of election preparations. BBC Alexander Demidov)