The audio of German military officers discussing top secret information was intercepted by Russia only because one of them logged in through an insecure line from a hotel room in Singapore, Defense Minister Boris Pistorius said Tuesday.
Addressing the leak in Berlin following an investigation by Germany's Military Counterintelligence Service, Pistorius insisted the incident was a one-off.
"Our communication systems were not compromised," he said.
On Friday, Russia's state-run media outlet Russia Today released details of a 38-minute call between senior German officers — including the chief of the air force — in which they discussed the hypothetical dispatch of Taurus cruise missiles to Ukraine as part of preparations for a meeting with Pistorius.
Chancellor Olaf Scholz is opposed to sending the missiles, and the issue has splintered his governing coalition.
One of the participants — reported to be Brigadier General Frank Gräfe — dialed into the WebEx call from a hotel room in Singapore where he was visiting an airshow.
Over the weekend, the government confirmed the veracity of the recording. Pistorius on Sunday called it a "hybrid disinformation attack" by Russia, although the recording published by Moscow was not faked.
Amid questions over the German military's security protocols, White House national security spokesperson John Kirby said this week that the leak was an “attempt by the Russians to try to sow discord and to try to show division.”
The U.K. also reacted with dismay to the leak, where the officers discussed how the British and French were delivering cruise missiles to Ukraine, with Gräfe apparently saying: "If we're asked about delivery methods. I know how the British do this. They always transport them in Ridgeback armored vehicles. They have several people on the ground."
That comes after Scholz publicly confirmed that British troops are on the ground in Ukraine helping Ukrainian forces use Storm Shadow cruise missiles.
On Tuesday, Pistorius said he had spoken with allies to reassure them. “The trust of allies in Germany remains unbroken,” he said in Berlin.
Meanwhile, the Kremlin is celebrating.
The Russian government's lead spokesperson Dmitry Peskov called for a full investigation of the recording, and said that the German ambassador to Russia had been summoned to explain apparent plans to attack Russia.
"We are yet to find out if the Bundeswehr is doing this on its own initiative. If so, the question is to what extent the Bundeswehr is controllable and to what extent Mr. Scholz controls it all, and whether it is part of Germany’s government policy," Peskov said, according to Russia's state-owned TASS news agency.