MOSCOW — Belarusan President Alexander Lukashenko walked off the stage Monday at a tractor plant in Minsk, Belarus, to workers chanting loudly for him to step down, as he struggles to contain mass anger in the wake of an election widely seen as fraudulent.

Such a scene would have been difficult to imagine before the Aug. 9 election, which has roiled the country and, for the first time in 26 years, threatened Lukashenko’s grip on power.

Under increasing pressure, and facing strikes at state-owned companies and mass protests, Lukashenko vowed Monday that he would have to be killed before he bent to demands for new elections.

“You are talking about unfair elections and want to have fair elections?” he asked the crowd of workers at the Minsk Wheeled Tractor Plant, who shouted “Yes” in response. “I am answering your question. We held elections. Until you kill me, there will be no other elections.”

The president said he would never yield to public pressure but conceded that he would be willing to share power under a new constitution.

“We cannot put the constitution into the hands of God knows who because there would be trouble in that case,” he told the workers, state news agency BelTA reported. Lukashenko said he was willing to redistribute presidential powers through constitutional changes, “but that won’t happen under pressure or through street protests.”

Later he appeared to reverse course, suggesting that new elections may be possible after a new constitution is passed.

But the opposition is likely to be wary of Lukashenko’s vague promise of future constitutional changes leading to possible new elections.

The protests were triggered by the official result, which gave Lukashenko 80.1 percent of the vote compared with 10.1 percent for rival Svetlana Tikhanovskaya. The unrest has also been fueled by violence against peaceful protesters by riot police.

The strikes at state-owned factories indicate that bedrock of support from Lukashenko’s traditional base is crumbling. Even workers at the state television and radio broadcaster Belteleradiocompany walked off their jobs to demand the resignation of the head of the Central Election Commission, the release of political prisoners, and new free and fair elections. Several state TV presenters have resigned.

In addition to the Minsk Wheeled Tractor Plant, strikes were reported at Belaruskali, one of the world’s biggest producers and exporters of potash fertilizer; the Minsk Automobile Plant; and the Belarusan Metallurgical Plant. Workers at the oil company Naftan and the Mozyr refinery also were on strike.

On Monday evening, protesters marched to the Minsk Detention Center No. 1 in central Minsk demanding the release of political prisoners. Another protest sprang up outside the Yanka Kupala National Theater, after Director Pavel Latushka was dismissed over an appeal by its performers to authorities to end violence against peaceful protesters and hold new elections.

Lukashenko has ruled Belarus since 1994 through flawed elections, disregarding constitutional term limits, jailing critics and election rivals, and cracking down on protests. But the depth of anger over the Aug. 9 election has put him under more pressure than before, prompting him to turn to Russia. Claiming that Belarus faces threats from external enemies, he has been seeking guarantees of support.

Tensions have increased in recent years between the two allies as Russia pushes Belarus to fulfill a 1999 agreement for a union of the two countries, on which Lukashenko has been stalling. But Lukashenko’s desperate appeals to Russian President Vladimir Putin over the weekend underscore that Russia remains Belarus’s most important partner.

The Belarusan prosecutor general said Monday that 122 people arrested during the protests were being held in isolation cells, and the Belarus Investigative Committee, responsible for investigating major crimes, said 600 people have filed complaints about alleged beatings while they were held in detention.

Abuses by riot police were revealed when some detainees were released in the past week. Graphic images of their injuries and bruises circulated on social media.

Health Minister Vladimir Karanik said two people were killed and 158 were injured in the protests.

Speaking to workers at the tractor plant, Lukashenko said that the strikes were having no effect and that most factories were still operating. He also visited the Minsk Automobile Plant afterward.

“Well, 150 or 200 people don’t make a difference,” he said at the tractor plant, referring to the strikes. “Whoever does not want to work and wants to leave, please, the gates are open,” he added as workers chanted “Go away!”

“You can keep on shouting,” he said amid heckling. “You are working people. You have always supported the president.”

Answering questions afterward, Lukashenko said no laws were broken during the election.

The Internet in Belarus faced new interruptions Monday, in an apparent effort by authorities to stymie protests organized through social media. Like Hong Kong’s demonstrations, the protests in Belarus have been spontaneous and leaderless, with Telegram channels and social media playing a key role.

Tikhanovskaya ran for the presidency after her husband, Sergei Tikhanovsky, a popular blogger and presidential candidate, was jailed. She united his campaign with those of two other candidates, former banker Viktor Babariko, who was jailed, and businessman Valery Tsepkalo, who was barred from running in the election and fled the country fearing arrest. Tikhanovskaya sent her children abroad before the vote and fled to Lithuania after the election following her effort to lodge a formal challenge against the election result at the Central Election Commission.

Tikhanovskaya said in a video address Monday that she was ready to be acting president of Belarus so that political prisoners could be released and new elections could be organized.

“I am ready to assume the responsibility and to act as the national leader during this period so that the country calms down and gets into the normal rhythm, and so that we release all political prisoners and rapidly prepare a legislative foundation and conditions for organizing a new presidential election — a real, fair and transparent election to be unconditionally accepted by the international community,” Tikhanovskaya said.