A local resident reported suspicious activity near a Milrem Robotics building on Betooni tänav, in Tallinn's Lasnamäe district, and Estonia's Emergency Response Center logged the fire report at 01:45 local time (22:45 UTC) on 15 August 2026. Fire crews had the blaze under control by 03:03 local time and then removed sections of the roof to find and extinguish remaining hot spots. No injuries were reported. Estonian prosecutors say preliminary evidence points to a deliberate, pre-planned arson at the building used by Milrem, the Estonian maker of the THeMIS unmanned ground vehicle, and three suspects have since been detained in Latvia.
Milrem's THeMIS ground vehicles are already deployed to Ukraine
Milrem Robotics builds robotic and autonomous systems for military and security use, best known for the tracked THeMIS unmanned ground vehicle. The platform has operated in Ukraine since 2022 on logistics runs, casualty evacuation and route-clearance missions. In June 2026, Milrem and Dutch partner VDL Defentec began handing over the first vehicles from a new production line set up to support a Netherlands-funded delivery of more than 100 THeMIS systems to Ukraine. Russia offered a reward in 2022 for the capture of a THeMIS unit, according to Mezha, a marker of how much attention the platform has drawn from the Russian side of the front.
Investigators call the fire deliberate and are examining a sabotage link
Estonian Prosecutor General Astrid Asi said a criminal investigation opened on evidence gathered by the Internal Security Service (ISS, Estonia's domestic intelligence agency known as KAPO) and the North Prefecture, Tallinn's police district, and that the Prosecutor's Office has asked a court to detain the identified suspects. "The investigation is currently in its early stages and possible motives are still being examined, including whether this may have been an attempted act of sabotage," Asi said, per ERR. ISS Director General Margo Palloson said the threat level facing Estonia has not changed in recent years: "Russia poses a long-term existential threat to Estonia, which means we must take into account possible Russian provocations and nonmilitary threats." Prime Minister Kristen Michal confirmed the suspects had been identified and that one line of inquiry concerns Russian involvement, adding that Estonia would "protect our people and our companies by any means necessary."
Three suspects were detained in Latvia
Estonian State Prosecutor Gardi Anderson said three suspects tied to the arson were detained in Latvia and that a Latvian court granted requests to remand two of them in custody, with a decision on the third expected shortly. "We are working with our Latvian colleagues to bring the suspects to Estonia," Anderson said. She confirmed the fire was intentional and planned in advance but declined to detail the investigation further, saying all possibilities, sabotage included, remain open. Milrem CEO Kuldar Väärsi told Postimees it was too early to assess the damage to the building.
The fourth hit on Europe's Ukraine-bound defence supply chain in eleven days
Tallinn is the fourth site tied to Ukraine's military supply chain to catch fire, explode, or come under threat within a matter of days this August. On 4 August, an explosive-laden drone was found next to a Ukrainian cargo aircraft at Leipzig/Halle Airport in Germany. On 10 August, a fire tore through the EMCO ammunition plant near Belitsa, Bulgaria. On 13 August, an explosion hit the KNDS Ammo Italy plant at Colleferro near Rome, though Italian investigators ruled out sabotage there within hours. Poland and the Baltic states have separately tightened protection around critical infrastructure this year as officials warn Moscow may seek to stage operations aimed at undermining support for Ukraine.
Wind conditions over Tallinn on 15 August
At 23:00 UTC on 14 August, close to when the fire was reported, the 80 m surface layer over Tallinn showed wind pushing northeast at 18.8 km/h. At 2,000 m the flow pushed east at 31.5 km/h; at 3,000 m it also pushed east, strengthening to 41.2 km/h, a markedly stronger flow aloft than the 18.8 km/h at the surface. At surface level, that flow would have carried smoke from the Betooni tänav building toward the northeast, away from central Tallinn. This reconstruction is based on reporting by ERR, LRT, Kyiv Post and Mezha, and on AirVeto's wind-model data for the event window. How AirVeto builds this field, and where it is reliable, is described on the methodology page.
Estonian and Latvian authorities are still working to transfer the three detained suspects to Tallinn, and the Prosecutor General's office has not said when it expects to reach a conclusion on whether the fire was ordinary criminal arson or a state-linked sabotage operation. For now, the case joins a growing list of unresolved fires and blasts at facilities that keep Ukraine's front line supplied.