Evincing Russian President Vladimir Putin’s escalating preparations for war, Russia boosted the gas reserves of its Kaliningrad exclave on Tuesday.

As reported by Kommersant, the Marshal Vasilevskiy gas resupply vessel docked with Kaliningrad’s offshore terminal. According to Gazprom, the vessel, which is the only one of its kind, has “174,000 cubic meters of reservoir capacity.” It’s a reflection of Putin’s concern that Kaliningrad may be cut off from overland gas supplies if Russia re-invades Ukraine. Russia’s fear is that Lithuania may shut off pipeline flows into Kaliningrad.