The first contingent of US troops, tanks and equipment taking part in the "Defender Europe 20" military exercise began arriving in the northern German port of Bremerhaven Friday, kicking off the the largest deployment of US-based forces in Europe in over 25 years.

In total, over 20,000 troops and 20,000 pieces of equipment are being shipped across the Atlantic, arriving at six European seaports. They will then transfer to staging areas and on to military maneuvers with European partners, the US Army said.

A significant part of the troops and equipment are expected to be deployed to Poland, Latvia, Lithuania, and Estonia.

The role of Russia

The mass movement of US troops across the Atlantic into Germany and eastern Europe is intended as a test of trans-Atlantic military cooperation and capability. It comes as NATO's Eastern European members are wary of Russia's more aggressive posture in the region.

The US army said that the Defender Europe 20 "demonstrates the US military's ability to deploy a large force to support NATO and respond to any crisis."

Claudia Major, an expert in security and defense policy at the German Institute for Security and International Affairs (SWP), told DW that Russia's Crimea annexation was a "wake up call" for Europe.

"The security order that Europe believed it had with Russia no longer worked. Russia was no longer a strategic partner. Europeans have to deal with the question again: 'how do we defend ourselves in Europe?'"

However, Lt. Gen. Martin Schelleis, German commander of the joint support service, said that Defender Europe 20 was not intended to be a sign of aggression towards Russia.

"Russia is not a reason for the exercise, military capabilities can only be rebuilt and maintained in the long term," he said.

Read More: NATO in a nutshell: What you need to know

Tanks on German roads?

Germany's central location means that the vast majority of the equipment heading east will be transferred along German roads and rail.

Both the German and US military have said they will try and avoid interrupting daily life, and transports are expected to take place during the night.

"If everything goes well, nobody will notice anything," said Schelleis. "From an operational perspective, we are primarily interested in whether our processes are capable of withstanding loads of this magnitude.

The long-term aim is to use the experience to strengthen NATO

"The exercise is essentially about the transit and transportation of troops," said Major, adding that NATO's eastern European partners in Poland and the Baltic states need to test their infrastructure and capacities.

Donald Trump on NATO: Top quotes Trump on NATO: A war of words Even before taking office, US President Donald Trump's relationship with NATO has been a tumultuous one, to say the least. He has disparaged the trans-Atlantic alliance, once describing it as "obsolete" and a relic of the Cold War. Here are Trump's most memorable quotes about the military alliance, even if they are at times false.

Donald Trump on NATO: Top quotes 'Days of the Soviet Union' While on the campaign trail in 2016, Trump made clear that he saw NATO as a relic of the Cold War. "You know, we're dealing with NATO from the days of the Soviet Union, which no longer exists. We need to either transition into terror or we need something else." But his remarks didn't account for how the alliance backed the US well after the collapse of the Soviet Union, especially in Afghanistan.

Donald Trump on NATO: Top quotes 'Germany owes vast sums' Trump has made defense spending his main talking point on NATO. But he has falsely accused member states of owing money to Washington, saying: "Germany owes vast sums of money to NATO, and the United States must be paid more for the powerful, and very expensive, defense it provides to Germany." The problem is NATO doesn't work like that. No money is owed to the alliance for defense or otherwise.

Donald Trump on NATO: Top quotes 'Obsolete' Days before his inauguration, Trump caught NATO members off guard when he claimed the alliance was "obsolete" and threatened to withdraw support. "I said a long time ago that NATO had problems: Number one, it was obsolete, because it was designed many, many years ago." Months later, he retracted his statement, citing changes within the alliance. "Now they fight terrorism," he said.

Donald Trump on NATO: Top quotes 'Doesn't sound very smart' Trump had tended to lump trade between US allies with how much Washington spends on defense. "We are spending a fortune on military in order to lose $800 billion (in trade losses). That doesn't sound very smart to me," Trump said. The problem is that while NATO members have agreed to spend 2 percent of their GDP on defense, the alliance has nothing to do with international trade.

Donald Trump on NATO: Top quotes 'We are the schmucks' During a 2018 rally in Montana, Trump hit out at European allies, saying: "They want (us) to protect against Russia, and yet they pay billions of dollars to Russia, and we're the schmucks paying for the whole thing." Trump was referring to Russia as Europe's primary source for oil and natural gas, but he created a false dichotomy between energy reliance and NATO's defense spending goal.

Donald Trump on NATO: Top quotes 'Congratulations, you're in World War III' In an interview with Fox News, Trump was asked why the US should jump to the defense of NATO ally Montenegro if it was attacked. The president said he asked himself the same question, a remark that appeared to undermine the alliance's collective defense clause. Trump went on to describe Montenegrins as "very strong" and "very aggressive," and that that aggression risked starting World War III. Author: Lewis Sanders IV, Elliot Douglas



Additional reporting by Lisa Hänel

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