A brigade of heavily armed U.S. troops have deployed to Zagan, Poland to show Russia that if it dares to encroach on its territory, it will feel the full force of the NATO alliance. It is the show of defiance against Putin many NATO allies have been waiting for from the Trump administration.

The Third Armored Brigade Combat Team, 4th Infantry Division, consisting of 3,500 men, 144 armored vehicles and 87 tanks, participated in live exercises Monday, . It was the largest deployment of U.S. troops to Europe, since the fall of the Soviet Union. Kremlin spokesperson called the exercises a “security threat.”

As ’ (and, full disclosure, occasional Foxtrot Alpha contributor) Kyle Mizokami reports, the brigade is heavily armed:

The brigade is also equipped with 140 M2A3 Bradley infantry fighting vehicles, a similarly upgraded version of the original M2 Bradley. The Bradley is armed with a 30-millimeter Bushmaster cannon, two TOW anti-tank missiles in the ready position, and can carry up to seven infantrymen 3-4 ABCT’s Bradleys have the relatively new Commander’s Independent Thermal Viewer (CITV) that allows the vehicle commander his own thermal viewer separate from the gunner’s. A tall, boxy protrusion, the CITV allows the commander to look ahead at threats ahead and maintain situational awareness while the gunner engages targets.

This is one of many deployments that former president Barack Obama ordered, , at the insistence of the mostly eastern European members of NATO—especially Poland.

Here is what Gen. Ben Hodges, the commander of the U.S. Army in Europe, told :

“This is the largest ever U.S. deployment in Poland and it’s about deterrence... An outright attack by Russia is unlikely, but the best way to keep it unlikely is to do what we’re doing here today.”

Hodges made clear NATO believes the threat from Russia is real.

“Russian aggression takes many forms,” he said. “Cyber, misinformation, threatening other countries, Russian snap exercises. We’re serious — this is not just a training exercise. It’s to demonstrate a strategic message that you cannot violate the sovereignty of members of NATO ... Moscow will get the message — I’m confident of it. “

Poland, a former communist state. has long expressed concerns that it could face the same fate of Ukraine suffered in 2014, when Russian-backed rebels waged a war against Kyiv that has lasted more than two years. Moscow also annexed Crimea that same year.

Kyiv and even members of Congress from both sides of the aisle for Obama to provide Ukraine with offensive weapons, but he declined to do in fears the move would provoke Moscow even further. A series of peace talks between Kyiv, Moscow, the West and Russia-backed rebels have taken place since the conflict started to resolve the issue but to no avail.

In fact, , intense fighting is taking place in the small town of Avdiivka; the dozens are reported to have been killed in the fighting this month.

Seven Ukrainian troops have been killed since Sunday fighting against Russia-backed rebels in the…

The deployments should calm European leaders who have expressed concern over President Trump’s anti-NATO comments. EU President Donald Tusk Trump a “threat” Tuesday over his anti-NATO comments and suspiciously warm attitude towards Russian President Vladimir Putin, whom U.S. intelligence agencies accuse of hacking the 2016 U.S. election.

Though, unlike Ukraine, Poland is a NATO member, so other alliance states would be compelled to come to Warsaw’s aid in the event Russia did launch an attack. The recent U.S. deployments are a signal to Moscow that any move into NATO territory will be met with U.S. firepower.