What is Russia's Vladimir Putin planning?

When a former KGB officer became Russia's president more than two decades ago, the one question everyone in the West seemed to be asking was: "Who is Mr Putin?"

Today the question has changed to: "What is Mr Putin planning?"

The tens of thousands of Russian troops deployed near Ukraine's border; the increasing anti-Western rhetoric in Moscow; a Russian diplomatic initiative that looks more like an ultimatum to the West than a serious negotiation: are these preparations for a large-scale Russian military operation? An invasion of Ukraine? Is this a prelude to war?

Like most foreign journalists in Moscow, I have a telephone number for the Kremlin press office. What I don't have is a direct line into the mind of Vladimir Putin.

Only he, perhaps, knows what the plan is and, right now, at home and abroad, he's keeping everyone guessing.

• Is Russia preparing to invade Ukraine?

• What would be the fallout if Russia invaded Ukraine?

But some things are clear.

This week marks 30 years since the dissolution of the Soviet Union. President Putin once described that as "the greatest geopolitical tragedy of the 20th Century." He remains deeply resentful of how the Cold War ended: with Moscow losing territory, influence and empire.

"What was the break-up of the USSR? It was the break-up of historical Russia," Mr Putin said in a recent state TV documentary. "We lost 40% of our territory… much of what had been accumulated over 1,000 years was lost."

The Kremlin resents, too, Nato's post-Cold War enlargement to the east. Moscow accuses the West of breaking verbal promises that the alliance would not expand into Eastern Europe and the former Soviet space. Nato insists no such promises were given.

Can Russia undo what is done? It appears to be trying.

Last week, Deputy Foreign Minister Sergei Ryabkov unveiled draft security agreements that Moscow wants America to sign. They would provide a legally binding guarantee that Nato will give up military activity in Eastern Europe and Ukraine.

The proposals would appear to prohibit Nato deployments to countries that joined the alliance after 1997. Russia is also demanding an end to Nato enlargement in former Soviet territory.

In an online briefing, I suggested to Mr Ryabkov that what Russia is proposing is a "complete reassessment of the results of the Cold War".

"I wouldn't call it a re-examination of the results of the Cold War," he replied. "I would say we're re-evaluating the expansion the West has carried out in recent years against Russian interests. This has been done in different ways, using various resources, with hostile intent. Enough is enough."

Nato - a defensive alliance - denies it has any "hostile intent" towards Russia.

As for "enough is enough", Western governments say just that about the Kremlin's behaviour. Moscow's annexation of Crimea in 2014 and its military intervention in eastern Ukraine triggered Western sanctions and an image of Vladimir Putin's Russia as an aggressor. It is why the Russian troop build-up near Ukraine is causing such concern.

What happens if Russia fails to receive the security guarantees it is demanding?

"We'll deploy missiles. But this is your choice. We don't want this," says Dmitry Kiselev, who presents the most popular news show on Russian state TV and plays a key role in spreading the Kremlin's message to the public.

Mr Kiselev, who is under Western sanctions, also heads the giant state media holding Rossiya Segodnya.

"If Ukraine ever joins Nato or if Nato develops military infrastructure there, we will hold a gun to America's head. We have the military capability.

"Russia has the best weapons in the world - hypersonic ones. They'd reach America as fast as US or British weapons could reach Moscow from Ukraine. It would be the Cuban missile crisis all over again, but with a shorter flight time for the missiles."

"Is Russia prepared to use force to defend its red lines?" I ask Mr Kiselev.

"One hundred percent, because for Russia this is a question of life or death."

"But Russia is dictating to its neighbours," I continue. "You're saying that Kazakhstan, Azerbaijan, Moldova, all former Soviet republics can't have anything to do with Nato?"

"Countries are either lucky or they're unlucky to be next to Russia. That's the historical reality. They can't change that. It's the same as Mexico. It's either lucky or not to be close to America," Mr Kiselev says.

"It would be good to harmonise our interests and not put Russia in a position where missiles could reach us in four minutes," he adds. "Russia is ready to create a comparable, analogous threat, by deploying its weapons close to decision-making centres. But we are suggesting a way of avoiding this, of not creating threats. Otherwise, everyone will be turned into radioactive ash."

• Can a solution be found for war in Ukraine's east?

• What next for Ukraine after Putin-Biden talks?

So, is the Russian troop build-up near Ukraine coercive diplomacy? Is the Kremlin's aim to extract concessions and security guarantees from Washington without the need for war? If so, it is a high-stakes approach.

"There is a real danger of an inadvertent escalation, be it in the Donbas, along the Russian-Ukrainian border, or maybe in the Black Sea," says Andrei Kortunov, director general of the Russian International Affairs Council, a think tank linked to the Russian authorities.

"If you have tensions, if you have this very poisonous political atmosphere, if you have a lot of military activities, on the ground, in the air, the sea, there are risks something goes wrong. This could lead to a conflict no-one really wants."

And if there is a major conflict? The annexation of Crimea proved popular with the Russian public. But Russians have little appetite for a full-scale war with Ukraine or military confrontation with the West.

"I don't think that Russians are focused now on foreign policy success stories, real or imaginary," says Mr Kortunov. "The agenda is mostly domestic and the real concerns of Russians are connected to social and economic problems. I don't think Putin is in a position to get a couple of additional points if he starts an operation abroad."