Their Russian adversaries hunted them, looking for tattoos that would identify the Ukrainian men as ex-servicemen, and lists—compiled with the help of local collaborators—of potential Ukrainian resistance leaders. Many were caught, but those who survived are now part of a new strategy for the outgunned Ukrainian army. With a front-line stalemate stretching across the country, Kyiv is trying to get behind it in territory held by Moscow to “hit at least [a] a few teeth out of the Russian bite,” according to a Ukrainian official. The rebel network was activated in late July as Ukraine’s elite Special Operations Forces stepped up their own missions in occupied territory, including the use of armed drones. The approach has also been helped by the arrival of US truck-mounted guided missile launchers, called Himars, which have extended the Ukrainian military’s range up to 80 kilometers behind Russian front lines. The goal was to get behind enemy lines “and teach them chaos,” said the Ukrainian official, who asked not to be identified when discussing military strategy. “Just because they have a meat grinder doesn’t mean we have to deal with it,” the official said, referring to the Russian forces’ front-line artillery barrage. The attacks forced the Russians to spend time and resources defending their rear bases, slowing their ability to move supplies to the front. One of the most visible of Ukraine’s attacks on the occupied territories was the destruction of an air base in Crimea, accompanied by a series of explosions that put the peninsula on edge. Another was an explosion on a major railway bridge in Melitopol, according to another Ukrainian official. Ukraine’s efforts sometimes yield little. In the north, civilian drones search for Russian artillery units. But successful strikes are rare, the second official said, and Russian weapons have continued to target Kharkiv, Ukraine’s second-largest city. In the south, another military official said, Ukraine sends two-man sniper teams on weekly missions into the no-man’s land between Russian and Ukrainian positions. The aim is to deploy senior military commanders. “It’s very hard work, very slow, very dangerous,” the second official said. “But they’re chasing high-value targets – even one hit is great.” In occupied cities such as Melitopol, the guerrillas have shown their hand in recent weeks with a series of small explosions, including a car bomb attack driven by a Ukrainian collaborator, an official said. “That’s what the French resistance did — softening targets and infrastructure,” said a retired British special forces soldier who has trained the Ukrainians. A law enforcement officer stands guard after a reported drone attack on the Russian Black Sea Fleet headquarters in Sevastopol © Stringer/Reuters The cumulative impact rattles the Russians. In Crimea, Russian news agencies reported that the commander of the Black Sea Fleet had been replaced after the attack on the Saki airbase sent plumes of smoke into the sky and Russian tourists pouring from beaches. “The Russian system is busy trying to assign blame,” a Western official said. The attacks in Crimea, he said, underscored Ukraine’s ability to operate behind Russian lines “because of a combination of incredibly brave people and new capabilities.” It is difficult to assess whether the efforts have significantly degraded Russian military capabilities. The Western official said that the Ukrainians should be “preserved [this] activity level’ to have a meaningful impact.

The Russians have moved ammunition depots and command and control centers away from the front lines, but have continued to use artillery to destroy Ukrainian positions, a strategy that has given them control of a fifth of Ukrainian territory. In the past two weeks, the second Ukrainian official said, another 8,000 Russian paratroopers have taken up positions near Kherson, a Russian-held city that Ukraine wants to liberate, and in the area around the city of Mykolaiv, which is under constant Russian attack. . “From there, they can move anywhere they want within two hours,” he added. “It’s a lot of men.” However, Kyiv will be hoping that their tactic of trying to get behind the lines will also have a psychological impact on tired opponents. “Imagine you’re a Russian soldier, and day after day, there’s a bomb somewhere near you — do you think that soldier can sleep now?” the second Ukrainian official said.