Opposition-linked media outlets including tut.by and Nasha Niva reported clashes with police and that a police van had rammed into a crowd of protesters. The police said that one of its officers was hurt in the scuffles, with videos from the scene showing bloodied demonstrators.
Belarus' incumbent President Alexander Lukashenko wins landslide victory in the presidential elections, exit poll shows.
Lukashenko's main opposition challenger Svetlana Tikhanovskaya came second with 6.8%, according to the poll.
Tikhanouskaya entered the race after her husband, an anti-government blogger who meant to run, was jailed.
Voters in face masks were seen arriving at a Minsk polling station, with some wearing white bracelets after Tikhanovskaya asked her supporters to wear them.
Belarusians are heading to polling stations around the country on Sunday, the main voting day for them to elect their president.
Big queues had also formed at Belarusian embassies overseas, including in Moscow where hundreds were lined up outside the embassy only two hours before voting was due to end at 20:00 local time (17:00 GMT).
Military vehicles, soldiers and police had patrolled the capital Minsk in apparent readiness for a new crackdown.
She says that if she wins she will call fresh elections that include the entire opposition, including those now in detention.
Tsikhanouskaya has gathered massive rallies like this one, attended by thousands of supporters in towns and cities throughout the nation, something that has never happened in this tightly run dictatorship before. "Nothing will get out of control, I guarantee you".
Lukashenko, who has been in power since 1994 and is seeking a sixth term, has warned the opposition he is not planning to give up his "beloved" Belarus and security was dramatically tightened in the capital on Sunday. Western observers, who have regarded no election under Lukashenka to be free or fair, were not invited this time.
A 30-year-old make-up artist from Minsk said she had wanted to vote for Babaryko, and accused Lukashenko of clinging to power.