A bizarre mini civil war of sorts has erupted among rival Ukrainian security agencies, complete with a wild street shootout and police standoff which has threatened to create more political scandal for President Zelensky - whose office has issued a statement - in an unprecedented saga which seems straight from the plot of a Lioness episode.

Details of the fresh incident, aspects of which may still be unfolding, are murky but widespread videos and local reports say the overnight firefight left wounded in the streets of Kiev. It appears to have started when authorities were investigating an alleged Russian Federal Security Service (FSB) plot against a Russian opposition figure fighting alongside Ukraine forces. But the investigators came upon uncooperative Ukrainian agents among Ukraine's military intelligence (HUR).