The Pulsating Aurora Imaging System (PAIPS) is being deployed at the Kola Peninsula and is aimed to conduct stereo measurements of pulsating aurora with high temporal resolution (1 ms). Photometers are lens telescopes using multi-anode PMTs as a photosensors operating in a single photon-counting mode, which provides extremely high sensitivity of the detectors. In this work we present the results of the search and analysis of the fastest emissions measured in a form of UV-microbursts. These events were found in data of the imaging photometer at the Verkhnetulomsky observatory during 2021–2023. All possible anthropogenic and atmospheric sources of UV-microbursts are excluded. The probable source of UV-microbursts are relativistic electron microbursts, which are observed in satellite experiments at the same geomagnetic latitudes and have similar temporal characteristics. Satellite electron detectors measurements demonstrate that relativistic electron microbursts appear as clusters or series of sharp peaks. The same is observed in the PAIPS photometer.