Belarusian President Alexander Lukashenko is hardly known for soft diplomacy – but his most recent comments on the state of relations with Russia were surprisingly blunt.

“I can read between the lines and I understand the hints,” he said in a meeting with Russian press on Friday. “You should just say it out loud: destroy the country and become part of Russia.”

Russia and Belarus have notionally been a “union” state since 1997, but the reality is one of only limited integration. Wars in Georgia and Ukraine, and the annexation of Crimea, moreover, have raised serious questions about Russia’s “brotherliness” and its future intentions.

President Lukashenko’s specific complaint centred on a new tax regime for oil, which Russia is planning to introduce in the new year. The manoeuvre, which switches tax from exports to source, will likely cost the Belarusian economy billions of dollars it can’t afford to lose.

The changes were not only deliberate, Lukashenko seemed to be saying, but designed to undermine his country’s sovereignty and push the country further into Moscow’s embrace.

At the weekend, a local independent news outlet reported that the Belarusian leader had summoned a secret meeting with his top officials, and had resolved to “defend independence to the hilt”.

The reports were later denied by the president’s press secretary. But that didn’t seem to matter. They spoke to long-standing rumours that Vladimir Putin had something planned for Belarus. Perhaps, even, as a way out of his succession conundrum.

As it stands, the Russian constitution only allows for two consecutive terms as president. In other words, if Vladimir Putin wants to stay on past 2024, or to enjoy a veto on policy, or obtain widespread guarantees on security, wealth and power, he has a big decision to make.

Some dream of ‘integrating’ their closest ally — just as they dreamed of ‘integrating’ Crimea Konstantin Kalachyov, head of the Political Expert Group

He could change the constitutional term limit and stay on as president. Or he could enter into an arrangement as he did in 2008, when he swapped jobs with the prime minister, Dmitry Medvedev.

According to sources close to the Kremlin, neither option is considered ideal.

The Russian president has “no desire to join the ranks of dictators ridiculed for clinging on to power”, one of the sources told The Independent. They needed a more “beautiful solution”.

A simple “castling” move as exercised in 2008-2011 wouldn’t do either. That experience was “painful” for Putin. He didn’t agree with much of the liberalisation agenda that Medvedev pushed (and he reversed most of the laws later.) More importantly, the trick wasn’t well received by Russians either, who took to the streets to protest.

The idea of Vladimir Putin heading a new union state of Belarus and Russia would, on one level, solve the conundrum. The president could instal a successor then watch over strategic decisions of security and direction from a new perch.

Of course, the scheme wouldn’t be easy to implement, and it isn't entirely clear how it would serve either country in the long term. Creating a real union state – as opposed to the notional one that exists on paper alone – would require much closer integration between Russia and Belarus. Most probably of the involuntary kind.

But the prospect doesn’t need to be particularly realistic to make President Lukashenko nervous, says Tatyana Stanovaya, founder and CEO of political analysis firm R.Politik. The problem for Lukashenko is he seems to have as limited a picture as the rest of us.

“No one will tell Lukashenko directly that Putin wants to create a union state,” says Stanovaya. “He only sees the top of the iceberg and doesn’t know how far Putin is ready to go. That’s obviously worrying for him.”

The Belarusian leader had apparently decided to go public after receiving “certain danger signals”, says Gleb Pavlovsky, a former Kremlin advisor and head of the Foundation for Effective Politics. That said, it was far from the first time that Lukashenko had reverted to such public diplomacy ahead of a new financial year.

“Lukashenko is manoeuvring as ever,” Pavlovsky told The Independent. “He wants to trade, but doesn’t want to sell. As long as he continues to trade, he’s safe enough.”

For the Kremlin, however, the dangers are clear. It desperately does not want its closest partner to disappear into a western orbit like Ukraine. But the Russian political elite has long been split on what to do about it.

Some dream of “integrating” their closest ally — just as they dreamed of “integrating” Crimea, says Konstantin Kalachyov, head of the Political Expert Group and an occasional Kremlin advisor. These same people do not consider Belarus to be an entirely separate nation.

It would seem such views persist at the top too.

“The president is worried about what will come after Lukashenko and already there are big problems,” Kalachyov told The Independent. “The economic relationship is no longer satisfactory for Russia, and ever since Crimea, Moscow has sensed Minsk no longer has its back politically.”

Several sources suggested that the Kremlin had stepped up “scenario planning” around Belarus in recent months. Of course, geopolitics rather than the succession issue are likely to be the main drivers behind this work. But Putin traditionally keeps his cards close to his chest, and apparently not even close colleagues are sure what his real intentions are.