ARKHANGELSK, February 25 (RIA Novosti) – The deputy director of a Russian military shipyard is hospitalized with head injuries following a beating by unknown attackers in the northern city of Severodvinsk, regional police reported on Monday.

Eduard Baal, who worked at the Zvyozdochka shipyard near the White Sea, was attacked at his apartment building after returning from work late on Friday, but the incident was revealed only on Monday.

“He has a brain concussion and numerous bruises on his body,” the regional Interior Ministry branch reported.

The attackers were allegedly armed with unspecified metal objects, the police said. The motive for the attack was not immediately clear.

Baal, who was temporarily standing in for his boss on the day of the attack, is in a satisfactory condition, plant spokesman Yevgeny Gladyshev said on Monday.

A criminal investigation has been started into the crime.

The Zyozdochka plant focuses on repairs of submarines, civil and military ships as well as scrapping obsolete nuclear submarines. It also has a gem-cutting department.