Less than a day before arriving in Moscow to salvage frayed ties with his Russian counterpart, Belarusian President Alexander Lukashenko said he no longer considers Russia a “brotherly nation.”

According to a television broadcast by Belsat, a Belarus-focused satellite channel headquartered in Warsaw, Poland, Lukashenko told a Monday Cabinet session that he no longer considered Minsk’s longtime regional ally a fraternal state “because I was informed that Russia is not receptive to it.”

News of Lukashenko’s comments, which were prompted by Russia’s refusal to provide financial compensation for changes to recently implemented export fees, filtered into the Kremlin midday Tuesday, just hours before he was set to head into a closed door meeting with President Vladimir Putin to discuss a range of topics aimed at improving bilateral cooperation.

Less than an hour before the high-level talks kicked off – their 12th face-to-face meeting this year – Russian Finance Minister Anton Siluanov countered Lukashenko’s comments by declaring a “loss of trust lately” with Moscow’s closest historical ally.

“We don’t trust the work of your customs,” Siluanov was quoted as telling an informal press gaggle in the Kremlin.

Bilateral ties faltered after Russia’s 2014 annexation of Crimea, which Lukashenko called “a bad precedent,” likely because the small former Soviet republic, which does not being to the European Union or NATO, is economically dependent on Moscow for trade, natural gas and other natural resources.

Diplomatic relations have been further strained by accusations of what Belarus calls artificially inflated taxes on oil and gas, while Russia has repeatedly expressed concerns about customs violations.

Russia, Belarus and Kazakhstan have a duty-free arrangement under which Moscow sends crude and oil products to Minsk with no export fee. Belarus then re-exports some of those goods, pocketing the associated charges.

Russia has used cheap energy exports and loans to Belarus as a way of keeping its former Soviet neighbor in Moscow’s geopolitical orbit, but the arrangement has become harder to sustain as Russia’s budget tightens, partially as a result of Western sanctions.

Russia also has accused Belarus of skimming payments on Russian duties by exporting gasoline and other oil products under the guise of aftermarket oil-based products, such as solvents and commercial chemicals.

Russia unexpectedly refused a request from Belarus for $310 million in compensation from a 2018 change in Russian oil taxes, Belarus’s deputy prime minister, Igor Lyashenko, told Reuters last week.

The Russian government in June approved changes in oil taxes that will see oil export duties being gradually cut over the next six years; but, as a result, Belarus believes it could lose $10.8 billion by 2024.

Finance Minister Siluanov said Russia never promised any compensation to Belarus over the tax changes.

“We consider such changes, including the tax maneuver in the oil and gas sector, as an internal matter of the Russian Federation,” he said.

According to The Moscow Times, the ongoing tensions didn’t stop the men from shaking hands before Tuesday’s meeting, where Lukashenko called on Putin to “not to drag old disputes into the new year.” 

“Overall, I believe our relations have been developing quite well,” Putin said upon opening the meeting, according to an official Kremlin press statement.

“Of course there are some problems, which is natural given the scope of our interaction,” Putin added, saying that both sides had come well prepared to address the most pressing issue – energy relations. “I suggest we listen to both sides even if we fail to reach any agreement,” he said.

Some information in this story is from Reuters.