Healey said the UK, working with Norway and other allies, monitored an Akula‑class attack submarine and two deep‑sea vessels linked to Russia’s Main Directorate of Deep‑Sea Research (GUGI), a secretive defense ministry unit that Western officials associate with seabed surveillance and sabotage capabilities. Reuters reported that the vessels did not enter UK territorial waters but operated in Britain’s exclusive economic zone and allied waters. Healey said no damage was done, but warned President Vladimir Putin that any attempt to target cables or pipelines would bring “serious consequences.”