The new equipment will be deployed mainly in eastern Poland -- NATO's eastern flank -- amid concern following Moscow's 2014 annexation of Crimea and the collapse of a landmark US-Russia arms treaty.

"We know how to modernise Poland's military and we will do it!" Defence Minister Mariusz Blaszczak tweeted.

He said planned purchases included submarines, marine helicopters, surface-to-air defence systems and 32 new fifth-generation fighters to replace Russian aircraft.

Blaszczak did not specify when the purchases will be made.

Earlier this month, the US and Poland inked a deal for Warsaw to buy American mobile rocket launchers worth $414 million.

In March last year, Warsaw signed a $4.75 billion contract to purchase a US-made Patriot anti-missile system.

Poland's right-wing government has been pushing for the US to open a permanent military base. Nearly 5,000 American troops are already stationed on a rotational basis as part of NATO operations.

According to Polish media, US Under Secretary of Defence for Policy John Rood is expected in Warsaw next month to announce a plan for an important US command centre in Poland.

With a defence budget equal to 2 percent of its gross domestic product (GDP), Poland is in the minority of NATO countries that have met the Western defence alliance's expenditure target.