Protests erupted in Minsk and other Belarusan cities Sunday night after election officials said exit polls showed longtime President Alexander Lukashenko had captured more than 80 percent of the vote.

The claim was met with broad skepticism amid widespread reports of irregularities following a campaign marked by government abuse.

Lidia Yermoshina, chief of the Central Election Commission of Belarus, said the count was based on returns from five of seven regions. Preliminary election results were to be announced on Monday.

In the lead-up to the polls Sunday, reports of intimidation by Lukashenko’s government came thick and fast: candidates were jailed; opposition activists, supporters and journalists arrested; news websites blocked; independent election monitors harassed.

As Lukashenko faced the toughest election of his 26 years in power, authorities tried to clear the field of competition, detaining his two main opponents and barring another from running. But Svetlana Tikhanovskaya, the wife of jailed candidate Sergei Tikhanovsky, united the three strongest opposition camps to fight Lukashenko in a campaign fronted by three women.

Long queues formed outside polling stations Sunday as voters heeded the opposition call to turn up in force. Yermoshina called the queues “an organized provocation” and “sabotage” by the opposition.

A heavy police and military presence in Minsk, the capital, blocked major roads and prevented people from approaching Independence Square.

One of the three women, Veronika Tsepkalo, had fled the country, the independent media site reported Sunday. Another, Maria Kolesnikova, was seized by police as she left campaign headquarters Saturday, but was released after a public outcry. Authorities arrested Tikhanovskaya’s campaign manager on Saturday for the second time in three days. Seven campaign volunteers were detained and another was missing, according to the opposition campaign.

Lukashenko, president since 1994, told journalists Sunday he did not count Tikhanovskaya as a serious rival. He denied the opposition had been targeted.

“Nobody has undertaken any repressions in violation of the law,” he said in Minsk. He vowed to maintain public order after the election.

“One cannot say that beginning tomorrow, the country will be embroiled in chaos and a civil war,” he said. “Nothing will get out of control, I guarantee you that.”

Andrei, a 30-year-old businessman voting outside Minsk, said the opposition had little chance of victory because the authorities would not allow it.

“This election would be close if all the real opponents were registered and out of prison. My candidate is in prison,” he said.

“The Central Election Commission will add in any necessary additional votes to make sure Lukashenko wins,” Andrei said. Like others, he declined to give his last name for fear of repercussions.

Valera, a mechanic, called the vote “meaningless, like a fight between an elephant and a small dog. The elephant will win.”

Internet service in Belarus was interrupted Sunday, restricting access to social media. Telegram channels used by election observers were shut down.

Late Saturday, security officials in black clothing and balaclavas seized young men who had been staging a small, peaceful protest in Minsk and forced them into vans. Earlier, police broke up a bicycle race held as a call for more freedom.

Lukashenko, 65, has changed the constitution, jailed opponents, barred rivals from running and cracked down against protests. More than 1,300 opposition supporters have been arrested since May, according to the rights group Viasna, as have dozens of journalists, bloggers, activists and independent election observers.

Tikhanovskaya, 37, sent her two children abroad after receiving a phone threat. On the eve of the election, she moved out of her apartment to a secret location, fearing arrest.

Lukashenko has lost popularity amid the country’s economic stagnation and his handling of the coronavirus pandemic, which he has dismissed as “mass psychosis.” But analysts — and the opposition — predicted that authorities would declare the result in Lukashenko’s favor and move swiftly to crush opposition protests, as in the past.

Sergei, 39, a transport company manager, said he did not see the inexperienced Tikhanovskaya as a likely president but voted for her anyway. “Lukashenko will be declared the winner whatever happens. There will be protests if he wins — what will be their outcome? People will rally and then go home.”

Dozens of independent election observers were reportedly detained, harassed or blocked. Two independent observers, Veronika Romanovskaya, 55, and Natalia Belyaeva, 46, said the local election commission used the pandemic as a pretext to prevent them from entering polling stations.

Independent observers said the number of votes at some stations exceeded registered voters.

Anastasia Matchenko of Zubr, a group monitoring the count, reported at least 828 cases of observers’ counts on turnout contradicting official figures.

The Central Election Commission reported high turnout in early voting from Tuesday to Saturday. But Romanovskaya and Belyaeva said the official figure was at least double the number of voters they had tracked, a finding also reported by other independent observers.

Svetlana Fominskaya, an observer at a Minsk polling station last week, said on social media that on Aug. 4, she counted 32 people voting. The official figure given was 131. On Aug. 8, 57 people voted, she said, but the official figure was 252.

In the final days of the campaign, pro-Lukashenko advertisements surfaced on YouTube depicting explosions, riots and other unrest amid his warnings that the opposition wanted chaos and destruction.

Lukashenko has portrayed his opponents as agents of foreign forces and has repeatedly warned of a tough crackdown should people take to the streets to protest the election results.

Tikhanovskaya says she has no political ambitions and decided to run only because her husband was jailed. Her campaign electrified Belarusians hungry for change.

The decision by major opposition campaigns to unite against Lukashenko took authorities by surprise. Tikhanovskaya mounted a surprisingly strong challenge, attracting tens of thousands to rallies in Minsk and other cities. The opposition’s central pledge is to hold new free and fair elections in which all candidates could compete.

Tikhanovskaya joined with the campaigns of former banker Victor Babariko, who is in jail on fraud charges that he says are politically motivated, and Valery Tsepkalo, a former ambassador to the United States and founder of a high-tech business park who was denied registration as a candidate and fled the country.

The other faces fronting the opposition campaign are Babariko’s campaign manager, Kolesnikova, detained Saturday, and Tsepkalo’s wife, Veronika.

Pavel, 31, an IT manager voting Sunday, said he was sure Lukashenko would lose but still be declared the victor.

“But the elections will demonstrate to the elite that Lukashenko is weak,” he said.

Anastasia Shpakovskaya in Minsk contributed to this report.