Polish leaders have held a welcome ceremony for the biggest deployment of US troops to Europe in decades.

Meanwhile, Russia called the deployment a threat to its own security.

The ceremony on Saturday in the western Polish town of Zagan comes 23 years after the last Soviet troops left the country.

The move also marks a new historic moment – the first time any Western forces are being deployed on a continuous basis to NATO’s eastern flank.

CNN reports there are also 2,400 pieces of military equipment including tanks sent over.

Polish Prime Minister Beata Szydlo stood before US and Polish soldiers and called it 'an important day for Poland, for Europe, for our common defense'.

Defence Minister Antoni Macierewicz told the troops that 'we waited for you for a very long time, for decades'.

American soldiers are welcomed to the Polish town of Zagan

The Kremlin said they see the bolstering of NATO as a 'threat'

The government organized several other events across the country to welcome the Americans from Fort Carson, Colorado.

It is likely these relations will not be the same over the next four years. President Elect Donald Trump has been a vocal opponent of NATO.

Last July he tweeted: 'My statement on NATO being obsolete and disproportionately too expensive (and unfair) for the U.S. are now, finally, receiving plaudits!'

Trump has stated he thinks NATO is 'obsolete' and 'too expensive'

This goes along with Trump's desire to improve America's ties with Russia. He said having a good relationship with Russia is a good thing and 'only "stupid" people, or fools' think otherwise.

Kremlin spokesman Dmitri Peskov said: ' We see it as a threat to us. This is an action that threatens our interests, our security, moreover, this is a third nation (apart from Russia and Poland) that is increasing its military presence near our borders in Europe, and it’s not even a European nation.'

'One thousand or 10,000 — we’re talking about the increase of military presence. There’s nothing to add.'

Prime Minister of Poland Beata Szydlo welcomed US troops to the ceremony

American soldiers attend the official welcome ceremony in Zagan