MINSK, Belarus — Tens of thousands of people marched on the palace of President Aleksandr G. Lukashenko of Belarus on Sunday, demanding he resign, as large-scale protests against the longtime, authoritarian leader entered their fourth week.
The crowd appeared to be at least as large as those of the previous two Sundays, when estimates put the protesters’ numbers at more than 100,000. The protests generally stayed peaceful, and for the third weekend in a row, the authorities refrained from widespread violence or mass detentions.
The large turnout indicated that the explosion of popular anger against Mr. Lukashenko that began with the Aug. 9 presidential election is nowhere close to abating. He claimed a landslide victory that is widely believed to have been falsified, and responded to the mass demonstrations that followed with a violent crackdown.
Belarus, like Ukraine, is a strategically located former Soviet republic, wedged between Russia and the former eastern bloc nations that have become democracies and joined NATO and the European Union. Mr. Lukashenko, who turned 66 on Sunday, has led Belarus since 1994, aligning himself with Russia while building a government tougher on political dissent than any other in Europe.
On Sunday, protesters marched through the main streets of Minsk, the capital, past a war monument encircled by razor wire and camouflage-clad soldiers and toward the Independence Palace, one of Mr. Lukashenko’s residences. At the palace, the protesters stopped when they were met by an imposing line of riot police officers that was backed by at least three military armored personnel carriers.
They chanted, “Go away!” in the direction of the palace. Since it was his birthday, there was also: “Lukashenko, come out! We will congratulate you!”
Mr. Lukashenko did not come out, but his press secretary released a photograph of him in a white T-shirt and black bulletproof vest in front of the palace, clutching a rifle.
“People have gotten tired of everything and stopped being afraid,” said Karina Romanovskaya, a 37-year-old protester who works in retail, shortly after a column of riot police officers marched by to chants of “Shame!”
“I am proud to live in such a wonderful country,” she said.
But a path to unseating Mr. Lukashenko, who insists the West is fomenting the demonstrations, remains far from clear. He faced a backlash after mass beatings and the detention of thousands of protesters in the days after the election and is now avoiding scenes of violent repression that could discredit him further.
Instead, he appears determined to wait out the protests, detaining activists and expelling foreign journalists while touting the backing of his most important ally, President Vladimir V. Putin of Russia. Mr. Putin recently said that Russian law enforcement officers were prepared to come to Mr. Lukashenko’s defense should the situation in Belarus spin “out of control.”
Mr. Lukashenko’s political opponents have stressed that they are not trying to loosen ties between Belarus, a country of 9.5 million people, and Russia — well aware of what happened after a popular uprising toppled a pro-Moscow president of Ukraine in 2014. Russia seized Crimea from Ukraine and backed a separatist insurgency in eastern Ukraine.
To underscore the bond between Mr. Putin and Mr. Lukashenko, the Kremlin said the Russian president wished his counterpart a happy birthday in a phone call on Sunday and invited him to a meeting in Moscow in the coming weeks. It was at least their fourth phone call this month.
The two leaders “confirmed a mutual determination to further strengthen the Russian-Belarusian alliance and broaden mutually beneficial cooperation in all directions,” the Kremlin said.