On 13 January 2025, NATO commenced ‘Baltic Sentry’ in response to recent incidents involving damage to critical undersea infrastructure (CUI) on the Baltic seabed. In the wake of these incidents, political and public debate has focused on whether the damage was caused by commercial ships dragging their anchors across the seabed. To counter the risk of re-occurrence, ‘Baltic Sentry’ is designed to deliver focused deterrence through enhanced surveillance presence across the region.
“We’re the eyes and the ears,” Commodore Arjen Warnaar – a Royal Netherlands Navy (RNLN) officer and COM SNMG1 – told Naval News onboard his flagship, the RNLN’s De Zeven Provincien-class frigate HNLMS Tromp, during a media visit to ‘Baltic Sentry’ activities conducted in waters between Estonia and Finland. In this sense, ‘Baltic Sentry’ aims to build deterrence through enhanced monitoring to develop an increasingly integrated and comprehensive maritime surveillance picture.
Cdre Warnaar illustrated the ‘Baltic Sentry’ aim through drawing parallels to civilian law enforcement in a domestic neighbourhood. “If there’s something going on there, for example houses being broken into, what tends to happen is the police are informed, and they conduct more intensive patrols. That gives a clear message to perpetrators. It’s more or less the same here,” he explained.
“We know something has happened. We’re increasing our patrols. We’re showing ourselves. We’re monitoring basically everything here at the moment. That sends a clear message.”
“If something is going to happen here, it is highly likely we’ll detect it,”
– Commodore Arjen Warnaar
In what is a multi-domain maritime response in ‘Baltic Sentry’ to the CUI risk, NATO Allied Maritime Command’s (MARCOM’s) two North Atlantic-focused standing naval forces – SNMG1, and Standing NATO Mine Counter Measures Group 1 (SNMCMG1) – provide the ‘hub’ around which a range of ‘spokes’ are being added to strengthen this deterrent presence in the Baltic. Such ‘spokes’ include national naval task groups deployed by regional navies; maritime patrol aircraft and fighter-attack aircraft (the latter including Netherlands F-35As); sensor networks including satellite connectivity; and national and regional MOCs.
In the latter instance, the connectivity to national MOCs demonstrates the geographical extent of the integrated monitoring and surveillance network ‘Baltic Sentry’ is building across the region.
“I’m connected to all the local maritime headquarters – Finnish, Estonian, Latvian, Lithuanian, Swedish, Danish, German, and Polish …. Eight out of the nine countries bordering the Baltic are NATO countries … [and] I’m a NATO task group. This is all interconnected,” said Cdre Warnaar. “So, we’re more or less drawing a complete network over the Baltic.”
“There are already a lot of ships here. We tend to focus on SNMG1, but I’ve got a very short link to all the Finnish and Estonian patrol ships already in this area. So, if I detect anything, I report it to them, and they’ll [respond quickly],” he added.
Underlining the point that ‘Baltic Sentry’ provides overall surveillance presence, national agencies (including navies and coastguards) provide response to incidents occurring within their own 12 nautical mile territorial waters. For incidents outside such waters, other options exist including approaching the flag state of any ship perceived to have been involved.
In providing surveillance and wider deterrence presence, ‘Baltic Sentry’ and its assembled maritime assets build the baseline for the activity. “SNMG1 is one of NATO’s four ‘first responders’,” said Cdre Warnaar – the other two being the Mediterranean-focused SNMG2 and SNMCMG2. “If anything happens anywhere in the NATO areas, we’re the first ones to respond.”
As regards how ‘Baltic Sentry’ helps enhance such response, “First of all, we’re going to build our picture,” Cdre Warnaar explained. “These are international waterways; there’s a lot of shipping …. Once we know what the pattern of life is supposed to look like – and that’s not really difficult; we have that picture pretty quickly – we can start to look at the anomalies: what doesn’t fit in; what is strange.”
“An example of something that would be strange is a large ship, [sailing] with some speed, towing its anchor. Now, that’s something that shouldn’t be happening. The next questions would be ‘why is the ship doing that’ and ‘what could the results be’?” Cdre Warnaar said.
“Once you detect something like that, it’ll be easy for us to start doing something about it,” the commodore continued. “Get in contact with that ship; make sure the local authorities know about it; and, if that ship is not willing to correct what it’s doing, facilitate an interception by the local authorities to have them stop it.” “The threat to CUI seems to be new, but actually it is not. We’ve had threats to it before,” said Cdre Warnaar. “At that time, we couldn’t point a finger at who it might have been. We think we know who it might have been now, and therefore we can act.”
