The Pentagon announced today that a company of paratroopers arrives in Poland on Wednesday to begin exercises, underscoring the department’s assertion that “Russia’s aggression in Ukraine has renewed our resolve to strengthening NATO’s defense plans and capabilities, and to demonstrate our continued commitment to collective defense in reinforcing our NATO allies in Central and Eastern Europe.”

Defense Department press secretary Rear Adm. John Kirby said the paratroopers come from the U.S. Army Europe’s 173rd Infantry Brigade Combat Team, Airborne, based in Vicenza, Italy.

“This new exercise is the first in a series of expanded U.S. land force training activities in Poland and the Baltic region that are scheduled to take place for the next few months and beyond. Additional companies from the 173rd will move in the coming days to Lithuania, Latvia, and Estonia for similar exercises,” Kirby said.

The company-sized contingents will number about 150 soldiers each, which could vary according to the exercise, he added, but will “roughly” total 600 personnel for the four countries.

“And what we’re after here is a persistent presence, a persistent rotational presence in these exercises,” Kirby continued. “So, we’re going to start, the troops will be in place in all four countries, probably by the end of this weekend, maybe Monday. As we get into all four countries, the exercises will last about a month or so. But then we will rotate fresh troops in for more exercises.”

“How far this will go? I can’t give you a specific, you know, deadline or timeline on it, but we’re looking at trying to keep this rotational presence persistent throughout the rest of this year. But beyond that, it could go beyond the end of this year. We just don’t know. We’re just going to have to see how it goes.”

Kirby acknowledged that the exercises — “real infantry training…that’s not insignificant” — could expand to other countries in the region.

“And we’re in discussions with our NATO allies and partners right now. It very well could, but right now it’s going to start with those four countries,” he said, adding that “these particular exercises were additive” since the Ukraine crisis came to a head and the U.S. sought ways “to reassure our allies and partners.”

“I think the message is to the people of Poland and Lithuania, Latvia, Estonia, that the United States takes seriously our obligations under article 5 of the NATO alliance, even though these aren’t NATO exercises. It’s a very tangible representation of our commitment to our security obligations in Europe, and the message is to the people of those countries and to the alliance that we do take it seriously. And we encourage our NATO partners to likewise look for opportunities of their own to do this same kind of thing for one another. And I think if there’s a message to Moscow, it is the same exact message that we take our obligations very, very seriously on the continent of Europe.”

Kirby stressed that the Pentagon is under no obligation to inform Russia of the exercises.

He said the exercises swung into motion after Defense Secretary Chuck Hagel “was pretty clear with the military leadership that he wanted to look for a wide range of opportunities through which we could continue to reassure our partners in Europe.”

Sen. John McCain (R-Ariz.) noted today, though, that the administration thumbed its nose at Poland long ago.

“We should have set up a deal where our energy over time could be supplied to them to eliminate over time their reliance. We should take them into NATO,” McCain said on Don Imus’ show when asked about how to handle Ukraine. “We should restore the missile defense systems that we canceled in the Czech Republic and Poland.”

“There’s a broad variety of things that we can do… What we do is wag our finger at [Russia] and then they do it and then we wag our finger at them again. The United States of America has lost credibility and that credibility has affected all over — all over the world and it really is — it’s the worst I’ve ever seen.”

The Navy is moving another warship, USS Taylor, to the Black Sea in the coming days. Kirby said today that there have been no more Russian warplane flyovers of the USS Donald Cook since the incident two weeks ago.