Polish President Andrzej Duda on Monday hailed the "historic" presence of US soldiers on his country's soil, saying it would reinforce Poland's security within NATO.

The US armoured brigade of some 3,500 troops as well as tanks and heavy equipment arrived in Poland this month, one of the largest deployments of US forces in Europe since the Cold War.

"This moment is historic, because it changes the model in our part of Europe," Duda said at the launch of a joint exercise of Polish and American troops in Zagan, a town near the German border.

He was joined by Lieutenant General Ben Hodges, the US Army commander in Europe.

The previous US administration of president Barack Obama ordered the deployment to reassure NATO allies in eastern Europe after Russia's annexation of Crimea from Ukraine in 2014.

The Kremlin has denounced the operation as a "threat" to its security.

Although President Donald Trump has said he wants to ease tensions with Moscow, the deployments remain in place for now.

Three decades ago, the Zagan garrison which is hosting the US troops housed "another army which we had not invited and which we had to treat as allies," Duda said, referring to former Soviet troops in then-communist Poland.

The so-called "Iron Brigade", from Fort Carson in Colorado, will also be deployed in rotation in six other NATO members -- the three Baltic states as well as Bulgaria, Hungary and Romania.