Under the heightened combat readiness level, soldiers were ordered to return to their units, while all holidays and business trips were put on hold.
The Polish army is also carrying out a review of its supplies and reserves, the website reported.
It quoted a Polish army officer it did not name as saying that further action depended on the development of the situation in Ukraine and the movement of Russian troops.
Russian President Vladimir Putin in the early hours of Thursday morning announced a "special military operation" against Ukraine to eliminate what he said was a serious threat against his country, the Reuters news agency reported.
Poland on Thursday condemned Russia's military attack on Ukraine and vowed to support its eastern neighbour.
(tf/gs)
Source: onet.pl