A rare confrontation between two of Ukraine’s security agencies broke out in Kyiv on September 2 while authorities were investigating an alleged Russian Federal Security Service (FSB) plot against a Russian opposition figure fighting alongside Ukraine.

The incident involved officers from the Security Service of Ukraine (SBU) and Ukraine’s military intelligence agency, the HUR. According to Ukraine’s Prosecutor General’s Office, SBU officers came under armed attack by “one of the units of the Defense Forces of Ukraine” while carrying out investigative actions connected to the alleged Russian plot.

The SBU said its officers were conducting urgent investigative measures to collect and document evidence in a pre-trial investigation into a terrorist attack allegedly being prepared by Russian intelligence services. During a search at a location on Shumskoho Street in Kyiv’s Dniprovskyi district, a group of people allegedly attempted to obstruct the operation and used vehicles to prevent investigators from moving through the area.

The SBU said its Special Operations Centre Alpha was deployed to stop the armed resistance and protect the officers involved in the investigation.

“In the process of putting an end to the armed resistance, the law enforcement officers used weapons,” the SBU said.