noun, noun which may take the genitive case particle 'no'
high alert; state of high alert; on alert
Refers to a heightened security or readiness posture, often used in news reports about police, military, or disaster preparedness.
警察はテロに備えて厳戒態勢を敷いた。
The police were on high alert against terrorism.
空港は厳戒態
The airport was under tight security in a state of high alert.