Dereliction of duty
News of the purge has been trickling out through official Russian news agencies including TASS and Interfax. But it an article in The Moscow Times blamed "chaos" in the Baltic Fleet's command structure for the dramatic move, citing the Russian Defence Ministry as accusing the officers of dereliction of duty.
"On June 29, the Russian Defence Ministry announced it was purging the entire senior and mid-level command of the Baltic Fleet. It was a dramatic move that suggested deep structural problems within the fleet command. In total, 50 officers were dismissed from their post, including the fleet commander, Vice Admiral Viktor Kravchuk, and his chief of staff, Vice Admiral Sergei Popov," The Moscow Times report reads.
"Not since Stalin's purges had so many officers been ousted at once."
Loyalty lacking?
"The courage of our sailors, the talent of our shipbuilders, and the spirit of our famous pioneers, explorers and naval commanders have confirmed Russia's status as a great sea power," Putin reportedly declared when visiting the Baltic base of Kaliningrad for Navy Day celebrations a year ago.
Something changed.
The Baltic Sea fleet is a backwater station, holding much less status than the Black Sea and Northern fleets. It is also relatively poorly equipped. Nevertheless, it consists of 128 surface ships, 71 landing craft, 72 combat jets and 44 air defence emplacements.
The significance of the region has surged in recent years with the defection from the former Soviet Union of the Baltic States, including Latvia, Lithuania and Estonia.
A small remaining Russian enclave on the Baltic coast, Kaliningrad, has since become a major thorn in NATO's side. Putin has built the outpost into a fortress and stationed long-range cruise missiles there that can reach deep into the heart of Europe.
So Putin would likely have been paying increased attention to the performance - and loyalty - of local commanders. Especially during recent spikes in tensions, such as the major BALTOPS 2016 exercise in which the massed warships of Europe and the United States practised amphibious assaults. Military commentators noted at the time that the Russian response had been unusually muted.
Blame game
The sudden purge came after what The Moscow Times called a month-long performance review in May-June.
The Russian Defence Ministry has reportedly since issued a statement which pulls no punches in its criticism of Vice Admiral Kravchuk. The commander had displayed "serious shortcomings in the organisation of combat training, daily activities of their forces, failure to take all necessary measures to improve personnel accommodations, inattention to their subordinates and distorted reports on the real state of affairs [in the fleet]."
Russian news service Fontanka.ru has speculated that an attempt to cover-up an unconfirmed collision between a Polish patrol boat and the Russian submarine Krasnodar may have been behind the purge.
But some Russian defence analysts have linked the removal of the entire officer structure to Putin's sidelining of Admiral Victor Chirkov, the head of Russia's navy, last year. Vice Admiral Kravchuk may have been perceived as having been "too close" to his former boss.
He has been replaced by Vice Admiral Alexander Nosatov as acting commander of the Baltic Fleet.