Poland's relations with Russia and its ally Belarus have deteriorated sharply since Moscow sent tens of thousands of troops into neighbouring Ukraine on Feb. 24, 2022, starting a war that is still being fought.

"Today, we need to prepare our forces for full-scale conflict, not an asymmetric-type conflict," army chief of staff General Wieslaw Kukula told a press conference.

"This forces us to find a good balance between the border mission and maintaining the intensity of training in the army," he said.

Speaking at the same event, deputy defence minister Pawel Bejda said that as of August, the number of troops guarding Poland's eastern border would be increased to 8,000 from the current 6,000, with an additional rearguard of 9,000 able to step up within 48 hours notice.

In May, Poland announced details of "East Shield", a 10 billion zloty ($2.5 billion) programme to beef up defences along its border with Belarus and Russia, which it plans to complete the plans by 2028.

The border with Belarus has been a flashpoint since migrants started flocking there in 2021 after Belarus opened travel agencies in the Middle East offering a new unofficial route into Europe - a move the European Union said was designed to create a crisis.

Warsaw has ramped up defence spending to more that 4% of its economic output this year in response to Russia's invasion of Ukraine.

Kukula also said the current high interest from candidates to join the army posed a dilemma over whether to take in more recruits than budgeted for at the expense of military equipment procurement, especially as he said interest was expected to start declining sharply from 2027.

The size of the armed forces stood at about 190,000 personnel at the end of last year, including ground, air, naval, special forces and territorial defence forces. Poland plans to increase this to 300,000 troops within a few years.