Polish President Bronislaw Komorowski has signed into law a new national defense strategy, saying it was made necessary by the instability and threats to security in neighboring Ukraine.

Komorowski said Wednesday the document is a reaction to the things that have "changed for worse to the east of Poland's borders, where an area of instability has emerged."

Among the negative factors, the document identified Russia's intensified policy of confrontation and its seizure of the Crimea Peninsula from Ukraine.

The strategy replaces a plan drawn up in 2007 and involves defense, political and economy structures on all levels, from the state government to local communities. Among other measures, Poland's nearly empty military bases in the east will be radically beefed up with troops and equipment, and reserve forces will undergo training.