Large crowds of protesters filled several parts of central Minsk, as police and heavily armed interior ministry troops indiscriminately attacked them, throwing stun grenades and reportedly firing rubber bullets. Authorities said at least one protester was killed.
The protests appeared to be swelling and demonstrators became increasingly emboldened, with police struggling to disperse them. On some streets, video appeared to show demonstrators using garbage dumpsters to build barricades and firing fireworks at the police officers.
Clashes were also reported in a number of other cities across Belarus, where protests broke out. Opposition social messenger channels urged people to gather on the streets and stand their ground against the police.
A nationwide strike has also been called for Tuesday.
The protests began Sunday night after official results from a presidential election gave Lukashenko 80% of the votes and his main opponent, Svetlana Tikhanovskaya, just 10%, amid suspicions of widespread vote rigging.
Tikhanovskaya, 37, a former teacher and stay-at-home mother, has become the head of the swelling protest movement and in the weeks before the election attracted the largest political demonstrations in Belarus since the fall of the Soviet Union. Lukashenko, 65, often known as "Europe's last dictator," has been in power for 26 years. The current protests are seen by many as an unprecedented challenges to his rule.
Tikhanovskaya accused Lukashenko of massive falsification in the election and demanded he hand over power peacefully to her so that new elections can be held.
Several thousand opposition supporters gathered peacefully in Minsk on Sunday night after the election, but were immediately violently attacked by riot police who used water cannons and stun grenades and detained and beat people seemingly at random. Several demonstrators were injured, at least one severely.
Lukashenko has dismissed Tikhanovskaya's demand he step down and on Monday even justified the crackdown, deriding the protesters as "sheep" controlled by European countries.
"I warned there won't be a Maidan, no matter who wanted it," Lukashenko said earlier on Monday, according to Belarus' state news agency, referring to Ukraine's popular revolution in 2014 that toppled an autocratic president. "And so it has to be quietened down, to be calmed down. The response will be adequate. We will not allow them to blow up the country."
Protesters returned Monday evening, after organizers advised them to buy helmets and goggles in anticipation of more police violence. Initially, small crowds in different groups moved towards the city center, where they were quickly attacked by police. But as the night wore on, the crowds grew in size, with thousands of people blocking roads and police officers seeming to struggle to contain them. Videos show that hundreds of cars stopped and honking in support. Meanwhile, explosions from stun grenades and fire works were heard consistently throughout the night.
Belarusian Interior Ministry said that one demonstrator was killed after an "improvised explosive device" went off in his hand while riot police were dismantling a barricade. It was not possible to verify the police's version of events.
The internet in Belarus has been partly shut down for two days, with many messenger apps not working properly. Belarus' government also refused to give journalists from most foreign news organizations permission to enter the country.
European countries on Monday expressed concern about the election and the crackdown on demonstrators. The president of the European Union, Charles Michel, tweeted for the government to respect "basic human rights" and the right to assemble.
Lukashenko recently sought to improve relations with Western countries as a counterweight to a more overbearing Russia, with which Belarus is already significantly integrated. The U.S. last year restored diplomatic relations with Belarus after a decade-long pause, caused by another crackdown by Lukashenko after an election in 2010.
Pompeo did not announce any U.S. action -- amid calls from some in the European Union for sanctions on Belarus -- nor did he offer suggestions for a path forward, such as calling for Lukashenko to hold new elections.
China, and Belarus' key ally, Russia, quickly recognized Lukashenko's re-election. Both President Vladimir Putin and China's leader, Xi Jinping, congratulated the Belarus president.
Tikhanovskaya said Sunday she would not join Monday's protests to "avoid provocations." Her team said authorities would surely use her presence at the protests as a pretext to jail her for allegedly inciting riots.
She has called for authorities to engage in negotiations with her for Lukashenko to leave power, and has promised to pursue legal options to challenge the election results. Her team has claimed that counts in polling stations in Minsk show that, in reality, she received five to six times more votes than Lukashenko. They also said the record number of early votes -- 40% of votes -- suggest widespread falsification.
At a press conference Monday morning, Tikhanovskaya called on anyone who believed their vote had been stolen "not to keep silent."
"The government [isn't] listening to us, it has completely broken with the people, but I should repeat that we are for peaceful transitions and the government ought to think about now how to hand over power through peaceful means, because at the moment they only have one way: violence against their own people," Tikhanovskaya said, according to the local Belarus' news outlet Tut.by.
Besides her appearance at the press conference and her brief appearance to file a complaint at her polling station on Monday, she has not been seen in public. For much of Sunday she was in hiding, worried that authorities would arrest her.
Tikhanovskaya has become an unexpected leader of the opposition. She reluctantly became a candidate after her husband, a popular blogger, was jailed and prevented from running against Lukashenko. But she has become a rallying figure for the opposition in her own right, joining with two other women, Veronika Tsepkalo and Maria Kolsenikova, to channel a wave of dissatisfaction with Lukashenko.
Discontent with Lukashenko has been fueled by a poor economy and weariness with his long rule and allegations of corruption. But it has also been boosted by his handling of the coronavirus pandemic, which Lukashenko has dismissed as a "hysteria." For months, the controversial leader has refused to impose significant quarantine measures despite rising cases and pleas from the World Health Organization.