NATO troops cross Poland's Vistula river in major readiness exercise

Some 20,000 soldiers from nine NATO countries transporting battle tanks, armoured personnel carriers and other military equipment crossed the Vistula river on Monday in a major NATO manoeuvre to test its readiness against Russia.

The operation - Dragon 24 - took place on Poland's longest river near Korzeniewo, which is about 100 kilometres south of Gdansk. Of the 20,000 soldiers, 15,000 were from Poland, the Polish armed forces said.

"We are showing what capabilities we have and we are combining this with the determination to use them," said NATO General Gunnar Brügner.

Overcoming a body of water is a key capability that an army needs in order to bring reinforcements to the front, Brügner said.

Dragon 24 is part of the larger NATO operation dubbed Steadfast Defender, which will last around four months and stretches from Norway to countries such as Romania. The defence alliance has mobilized around 90,000 soldiers in total for it.

Steadfast Defender is NATO's largest exercise since the Cold War.

The Vistula flows from the mountains in Poland's south to the Baltic Sea.

There are increasing warnings from European officials that Russia could be ready to test the solidarity of NATO allies at some point in the next few years.

The debate about the Western alliance's readiness for war gained more momentum in the wake of Russia's full-scale invasion of Ukraine just over two years ago.

Poland is one of Ukraine's most committed supporters and has also taken in almost 1 million war refugees from its eastern neighbour. It also serves as a logistical hub for military aid from the West.

The EU and NATO member feels particularly threatened by Russia due to its location and history. Many Poles are worried they could one day face a similar fate to the people of Ukraine.

Ukraine is not in NATO but wants to join, one reason given by Russia for invading. An attack on Poland would mean NATO has to intervene as per treaty.

Poland has recently invested heavily in modern weapons systems and spends around 4% of its gross domestic product on defence - or double NATO's 2% of GDP defence spending target.

Polish Prime Minister Donald Tusk recently said that Russian President Vladimir Putin's threats against the West should be taken "deadly seriously."