A stray remark by President Alexander G. Lukashenko of Belarus neatly encapsulated the imbalance in his relationship with President Vladimir V. Putin of Russia in recent years. As the cameras rolled, Mr. Putin thanked him in February for traveling to Moscow for a meeting.
Mr. Lukashenko replied: “As if I could not agree.”
For all his status as an authoritarian leader who has crushed opponents during 29 years in power, Mr. Lukashenko has had to tread carefully with the man who rules the giant country to his east. He even referred in comments to journalists on Thursday to his “big brother.” He did not name his senior sibling directly, but it was not necessary.
But the brief mutiny in Russia last month led by the mercenary leader Yevgeny V. Prigozhin has also given Mr. Lukashenko — at least temporarily — an opening to upend the relationship.
In the aftermath, the Belarusian leader has positioned himself as the mediator, stepping into help bring an end to the armed rebellion. He again gloried in the spotlight on Thursday, as the purveyor of information about the whereabouts of Mr. Prigozhin.
In doing so, he may be trying to reclaim some of the leverage he once had with Mr. Putin who, at 70, is two years his senior. For years, Mr. Lukashanko adeptly navigated between Russia and the West, playing both sides to his advantage.
After the Cold War, he professed loyalty to Moscow while maintaining a distance. He even responded favorably on occasion to attempts to draw Belarus closer to western Europe’s economic sphere.
Then in 2020, he had to call on the Kremlin for help, to shore up his decadeslong rule after he had cracked down on protests over an election widely derided as fraudulent. Since then, Belarus has been almost entirely dependent on Russia.
Russia used Belarus as a launchpad for its full-scale invasion of Ukraine in 2022, engendering sanctions and cementing its status as an international pariah. This year, in a further measure of a leader willing to defer to Mr. Putin without public complaint, Mr. Lukashenko even consented to having Moscow place nuclear weapons on his soil.
On June 24, as Mr. Prigozhin’s forces claimed control of the southwestern Russian city of Rostov-on-Don and began advancing toward Moscow, Mr. Lukashenko said in a statement that he had spoken to Mr. Putin and to Mr. Prigozhin. Hours later, the Belarusian state news agency released another statement saying that Mr. Prigozhin had agreed to halt his forces’ advance and take other steps to de-escalate the crisis.
What had looked like a possible coup attempt in Russia appeared to have ended with a diplomatic coup for Mr. Lukashenko.
Mr. Putin later called the Belarusian leader to thank him for his role in the talks, the Belarusian news agency said. Dmitri S. Peskov, the Kremlin spokesman, said that Mr. Lukashenko had personally offered to broker the deal, under which Mr. Prigozhin was allowed to go to Belarus and his fighters granted amnesty.
Three days after the uprising ended, Mr. Lukashenko said that the Wagner leader had arrived in Belarus. In Mr. Lukashenko’s account of his role, published by Belarusian state media, he said that Mr. Putin had raised the possibility of killing Mr. Prigozhin during the Wagner uprising, but that Mr. Lukashenko had argued against it, saying that “a bad peace is better than any war.”
The Belarusian leader said that he had then called Mr. Prigozhin, warning him that Mr. Putin intended to “squash him like a bug.” There has been no confirmation of those conversations from the Kremlin or Mr. Prigozhin, who has largely been silent since aborting his revolt.
Still, observers say that the most important factor in Mr. Lukashenko’s continued hold on power is that Mr. Putin remains in control in Russia.
The Belarusian leader appeared to acknowledge his reliance on Moscow last week, when he said he was motivated to intervene in the Wagner mutiny because “if Russia collapses, we will remain under the rubble — we will all die.”
Valerie Hopkins and Anatoly Kurmanaev contributed reporting.