noun, noun or participle which takes 'suru', transitive verb, noun which may take the genitive case particle 'no'
strict security; heavy guard; tight vigilance
Used for heightened security measures, often by police or military, in response to a threat or event. Common in compounds like 厳戒態勢 (strict security posture).
テロの脅威を受けて、空港は厳戒態勢を敷いた。
In response to the terrorist threat, the airport was placed under strict security.
The police are keeping the area under heavy guard.