MARSEC Level 3

MARSEC Level 3 is the exceptional security level at which further specific protective measures are maintained for a limited time when a security incident is probable or imminent, even if the specific target cannot be identified. ISPS Code Part A Section 2.1.11 defines security level 3 in those terms. SOLAS Chapter XI-2 Regulation 3 lets Contracting Governments set it; the ship security plan specifies the level-3 responses, such as suspended cargo operations, restricted movement, and guarded access. It is short-lived by design; MARSEC is the US designation under the MTSA.