martial law
noun [ U ] uk/ˌmɑː.ʃəl ˈlɔː/ us/ˌmɑːr.ʃəl ˈlɑː/
军事管制，戒严
the control of a city, country, etc. by an army instead of by its usual leaders
Renegade forces captured the capital and declared/imposed martial law. 叛军占领了首都，宣布实施军事管制。