Poland's Defence Minister Antoni Macierewicz speaks during his visit at Military Aviation Works No.1 in Lodz, Poland October 11, 2016. Agencja Gazeta/Marcin Stepien/via REUTERS

WARSAW (Reuters) - Poland expressed concerns on Wednesday over reports that Russia is sharply upgrading the firepower of its Baltic Fleet in Kaliningrad by adding warships with long-range cruise missiles.

Moscow has not confirmed the report in Russian daily Izvestia newspaper.

“This is an obvious cause for concern,” Defence Minister Antoni Macierewicz was quoted as saying by local news agency PAP. “Moving such ships on the Baltic (sea) changes the balance of power.”

Macierewicz is in Brussels for a NATO ministers’ meeting.