Two Ukrainian sabotage teams opened fire on each other near Kupyansk after mistakenly identifying one another as Russian forces, according to Russian security services cited by TASS and based on intercepted communications.

A source told the agency that the Ukrainian groups had been tasked with eliminating Russian soldiers in the area to create conditions for a breakthrough attempt. The plan also included staging the installation of Ukrainian flags to portray parts of the city as being under Kyiv’s control.

The operation collapsed almost immediately. According to the intercepts, five Ukrainian servicemen were killed and three wounded after the units misjudged the situation and entered into a firefight with their own side. Security officials attributed the failure to a lack of coordination between the groups, as well as to the haste and errors of the Ukrainian command, which deployed poorly prepared personnel.

Earlier, Chief of the General Staff of the Russian Armed Forces Valery Gerasimov informed President Vladimir Putin that Russian troops had fully secured Kupyansk.