Belarusian authorities have resumed detaining protesters in the country's capital as university students took to the streets to demand the resignation of the country's authoritarian leader after an election the political opposition has denounced as rigged.

Hundreds of students gathered outside universities in different parts of Minsk and marched through the city centre to the national Education Ministry, continuing a fourth straight week of mass post-election protests in Belarus.

President Alexander Lukashenko has dismissed protest participants as Western puppets and bristled at demands for him to step down after 26 years in power or start a dialogue with the opposition.

The demonstrators protesting on Tuesday chanted "Go away!", referring to Mr Lukashenko, and held banners demanding freedom for political prisoners.

Police moved to break up the crowds and detained some of the protesters.

Belarusian media reported that at least 18 students were detained.

Minsk police confirmed there were detentions but did not say how many.

According to the Viasna human rights centre, several university professors were also detained, and riot police beat up many of the detained students.

Valentin Stefanovich, a human rights advocate with the Viasna centre, called the beatings "an untoward reaction of the authorities to a peaceful protest".

"Students and universities in general are a highly explosive group," Mr Stefanovich told the Associated Press.

"The authorities are really scared of strikes starting in universities and are carrying out demonstrative intimidation acts."

After a ferocious crackdown on demonstrators in the first days after the August 9 election generated international outrage, the Belarusian government has avoided large-scale violence against demonstrators and sought to end the protests with threats and the selective jailing of activists.

Several organisers of strikes at top industrial plants have been detained.

On Tuesday, people started gathering near several large plants in support of the striking workers.

Belarusian prosecutors have opened a criminal probe against the opposition Co-ordination Council, accusing its members of undermining the country's security.

Last week, the country's courts handed 10-day jail sentences to two council members and summoned several others for questioning, including Svetlana Alexievich, the 2015 Nobel literature laureate.

Another council member, Lilia Vlasova, was detained on Monday.

The United States and the European Union have criticised the August 9 election that gave Mr Lukashenko a sixth term as neither free nor fair and urged Belarusian authorities to engage in a dialogue with the opposition.

Following a fierce dispersal of peaceful demonstrators in the days after the vote that left nearly 7,000 people detained, hundreds injured by police rubber bullets, stun grenades and beatings and at least three protesters dead, police stopped interfering with the demonstrations for the following two weeks, but last week again cranked up the pressure on demonstrators and began breaking up rallies.

The Belarusian government also cracked down hard on the news media, deporting some foreign journalists from the country and revoking the accreditation of many Belarusian journalists.

Two Moscow-based Associated Press journalists who were covering the recent protests in Belarus were deported to Russia on Saturday.

In addition, the AP's Belarusian journalists were told by the government that their press credentials had been revoked.

The Belarusian Association of Journalists said over the weekend that accreditation rights were also taken away from 17 Belarusians working for several other media, including Germany's ARD television, the BBC, Reuters and AFP, and US-funded radio Free Europe/Radio Liberty said five of its journalists lost their accreditation.

US and EU officials have strongly condemned the media crackdown.

The detention of hundreds of demonstrators did not deter the opposition from mounting another massive rally on Sunday, which saw an estimated 100,000 flood the streets of the Belarusian capital amid a heavy police presence.