MOSCOW – For nearly three months, protesters in Belarus were beaten, detained, sprayed with pepper spray, fined and exiled. But Oksana Koltovich, a bar and beauty salon owner in the state capital Minsk, is not put off.

“I have the feeling that we have entered a kind of tunnel,” said Ms. Koltovich on Monday by phone from Minsk on the way to another protest against President Aleksandr G. Lukashenko. “There is no going back. We go on and on and on. “

When hundreds of thousands of Belarusians took to the streets in August after Mr Lukashenko claimed a re-election victory widely viewed as fraudulent, many predicted that it would only be a matter of days or weeks before the longtime authoritarian leader resigned. Instead, Mr Lukashenko and most of the public who oppose him have embarked on a lengthy test of will, in which the future of their country is at stake.

The protesters come by the tens of thousands every Sunday and sing “Go away!” and waved the white-red-white flag of the opposition. Mr Lukashenko replied with waves of police raids and, supported by Russia, seems determined to wait for the protests.

“In such a tense situation, absolutely anything could turn out to be a trigger that overturns the system,” said Artyom Shraibman, a Minsk-based non-resident scholar at the Carnegie Moscow Center. “It could end in a week or not die for a year. No revolution ever went according to plan. “

On Monday, dispersed groups of workers across the country responded to calls for a general strike – the latest attempt by the loosely organized opposition movement to take the initiative. They were joined by university students who left their classes after an opposition march in Minsk on Sunday in which more than 100,000 people took part.

“The regime is unwilling to tell the truth, answer for its words or meet people’s demands,” said Svetlana Tikhanovskaya, Lukashenko’s electoral challenger, who was forced to flee Belarus, on Sunday as she went to the Called strike. “It means that this regime is not worthy of the Belarusian people.”

The course of events in Belarus, a former Soviet republic of 9.5 million people between Poland and Russia, could prove significant for Europe’s geopolitics. Belarus is Russia’s closest ally, and President Vladimir V. Putin has threatened to send Russian forces to stop the protests. Russian officials have portrayed the opposition movement as a West-backed campaign to pull Belarus out of its long-standing alliance with Moscow, although opposition leaders say they have no intention of breaking with Russia.

As if to reinforce this thought, the Belarusian authorities said on Monday that they had blocked the entry of 595 foreigners last week, most of them “tough young men with athletic builds” from Ukraine, Poland and Lithuania.

The use of force by the authorities to quell the protests appears to be escalating and fueling anger in Belarusian society. It was a fit of severe police violence at the beginning of the uprising that sparked the protests. Subsequently, and apparently under guidance from Moscow, security officers exercised lighter contact.

On Sunday, riot police threw stun grenades into a crowd of protesters, material posted on social media showed. Another video showed officers in body armor and balaclavas entering an apartment where protesters had taken refuge. One of the officers brandishes a young man with a baton, screams, and then gives a sickening blow.

“They understand that if they stop protesting, Lukashenko will not only win and choke everything with repression, but the last two months will have been in vain,” Shraibman said of the protesters.

Mr Lukashenko has indicated that he could be willing to compromise up to a certain point. He held a prison meeting with Belarusian opposition activists this month to discuss constitutional reform. He sat with the political prisoners at an oval wooden table with a floral centerpiece.

But Ms. Tikhanovskaya, who ran for president after Mr. Lukashenko imprisoned her husband, an opposition blogger, issued a “people’s ultimatum” on October 13th promising a general strike if Mr. Lukashenko does not come within two weeks resigned. The crowd at Minsk’s protest against the government on Sunday was the largest the city had seen in weeks.

On Monday, the first day of the strike, there appeared to be no strikes in the state-owned factories in Belarus, as witnessed in the first days of the protest movement in August. But some workers have quit their jobs, including Minsk Tractor Works, one of the most famous companies in the country, according to video footage from the factory premises.

In the town of Grodno on the Polish border, according to an independent trade union representative in Grodno, Liza Merlyak, more than 30 people were arrested when the police tried to break off protests in the local state fertilizer factory.

She said several dozen people who were supposed to work on Monday had not picked up their tools and that the strike affected the workshops within the plant. State industrial enterprises are at the core of the Belarusian economy, and Mr. Lukashenko has long occupied their workers as part of his political base.

“We believe that production must be slowed down or stopped because nobody will work in these workshops,” Ms. Merlyak said by telephone from Grodno.

Social media reports backing the opposition reported that people in Grodno, Minsk and elsewhere formed human “solidarity chains” in support of striking workers on Monday. Protests in Minsk continued after dark, even as police roamed downtown, grabbing people and dragging them into unmarked vans, videos showed.

An important audience for the protests is in Moscow. You are sending a message to Mr Putin: the longer he supports Mr Lukashenko, the more he risks losing the sympathy of the regular Belarusians, who have closer ties with Russia than perhaps any other people in Europe today.

Konstantin Zatulin, a Russian lawmaker specializing in the post-Soviet space, told the New York Times earlier this month that officials “at the highest levels in the Russian Federation” believed that Mr. Lukashenko would have to resign “sooner or later.”

Some protesters believe they must keep the pressure on until Putin takes a step.

“We are waiting, waiting until the regime may fall,” said Eduard Sventetsky, a strike leader at the tractor works in Minsk, who fled to Poland in August. “It depends on the leaders who sit in the Kremlin in Moscow.”

However, Mr Lukashenko seems to be betting that he can survive the demonstrators. Indeed, thousands of Belarusians, including many employees of the once thriving tech sector, have left the country in recent months to move to neighboring Ukraine, Lithuania and Poland.

Liza Moroz, a 23-year-old Belarusian journalist, moved to Kiev, Ukraine about two months ago. She took an active part in the August protests, but recently there have been few Instagram posts from acquaintances to keep her updated on what was going on at home. Most of her friends, she said, also left Belarus.

“I don’t know if I want to come back,” said Ms. Moroz over the phone. “Everything that happens – I think it will be a long time.”