Russian President Vladimir Putin just drew a bright red line for the United States: Don’t put any new nuclear missiles in Europe — or else.

As for the consequences if the US crosses that line, Putin was blunt: “We will be forced to take reciprocal measures.”

That’s the key message Putin had for the Trump administration on Wednesday when he delivered his annual state-of-the-nation address to the Duma (Russia’s parliament).

Putin spent most of the speech outlining domestic priorities for his country, such as reforming health care and improving the economy. But he made sure to spare no words about the rising tensions between Washington and Moscow over their missile arsenals.

Earlier this month, the Trump administration withdrew from the Intermediate-Range Nuclear Forces (INF) Treaty. Signed by President Ronald Reagan and Soviet leader Mikhail Gorbachev in December 1987, it prohibited the US and Russia from obtaining ground-launched cruise missiles that can fly between 310 and 3,420 miles.

The Obama administration previously accused Russia of violating the agreement by testing one of those weapons — a charge the Kremlin denies to this day. The Trump administration also says Russia violated it, and in early February, Secretary of State Mike Pompeo officially announced the US was leaving the pact as a result.

Russia responded accordingly, ending its participation in the treaty as well — the nuclear arms control version of, “You can’t fire me, I quit!”

There are now growing fears of a US-Russia arms race, as both countries are essentially free to develop the previously banned weapons.

Perhaps in an effort to let Washington know his limits for what can come next, Putin made it clear on Wednesday that US ground-based missiles in Europe would be unacceptable —because, as he put it, “They will only take 10 to 12 minutes to reach Moscow.”

“It’s a very serious threat to us, and we will have to respond,” he added.

And the response Putin promised is stark: “Russia will be forced to create and deploy new types of weapons that could be used not only against the territories where a direct threat to us comes from,” meaning Europe, “but also against the territories where decision-making centers directing the use of missile systems threatening us are located.”

In other words, we won’t just target Europe in response — we’ll also target key US locations, including places like Washington, DC.

Putin received strong applause from the crowd after that statement.

Don’t worry: Putin spoke more about sewage than war

The Russian leader’s comments definitely sound dire, but there is at least one reason for optimism: Putin has made these kinds of threats before.

During his same speech last year, he showed videos of his country’s nuclear weapons striking Florida. But in this year’s speech, he’s actually making it clear how the US can avoid a potential nuclear exchange with Russia.

So Putin may actually be trying to deescalate tensions with America — not increase them — with these pronouncements. He’s basically saying, “Sure, go ahead and make your new ground-based weapons. Just don’t put them near us; otherwise, we have to respond in kind.”

He also spent the vast majority of his time speaking about domestic issues — not a conflict with America — largely because of the country’s struggling economy.

“He only paid lip service to warmongering comments, but he spent most of the speech assuring Russians that he was aware of day-to-day hardships,” Alina Polyakova, a Russia expert at the Brookings Institution think tank in Washington, told me. “It’s amazing how much time he spent talking about sewage.”

The pessimistic read, though, is that Putin is merely setting the stage to build more weapons and potentially place them near European or American territory. Russia could lie and say it has evidence that America aims to put missiles in Europe as an excuse to go ahead and do what it was planning to all along.

And Putin did use some of his speech to discuss the deployment of nuclear-powered cruise missiles, intercontinental ballistic missiles, and underwater drones. Those announcements could rightfully be seen as provocative statements.

A lot, then, is riding on the US response. Does the Trump administration believe Putin is trying to calm tensions, or does it assume he’s merely trying to mask a massive weapons expansion? How Trump and his advisers answer that question could determine the trajectory of US-Russian relations for a long time to come.