Police in Belarus detained several dozen university students on Tuesday as they marked the first day of school with protests against strongman leader Alexander Lukashenko.
Hundreds of students took to the streets of the capital Minsk for the latest in three weeks of rallies rejecting the strongman's claim to have won a sixth term in elections last month and demanding he resign.
Students from several universities chanted "Fascists!" and "This is our city!"
Some attempted to form a human chain but were detained by riot police, with rights group Viasna saying more than 40 were arrested.
Thousands of Belarusians have been taking part in unprecedented protests since the August 9 election, which Lukashenko says he won with 80 percent of the vote but critics say was rigged.
More than 100,000 people have flooded the streets of Minsk for three straight weekends to demand the resignation of the 66-year-old strongman, who has ruled the ex-Soviet country since 1994.
Russian President Vladimir Putin has raised the possibility of sending military support if Belarus "starts to get out of control" and Lukashenko has been pictured brandishing an assault rifle during protests.
Lukashenko has dismissed the calls to resign, brushed off the idea of holding new elections and instead detained protesters and members of the opposition.
On Tuesday, Lukashenko vowed to punish EU members Estonia, Latvia and Lithuania after they banned him and 29 other high-ranking officials over the election and subsequent crackdown.
"We will simply try to solve this problem with economic methods," Lukashenko said on a visit to the western city of Baranovichi, suggesting he could re-rout Belarusian cargo from Baltic ports and send it via Russia.
"Of course, it would be a little bit disadvantageous for us. But we can agree with Russians on tariffs."
Lukashenko also accused the opposition of wanting to cut the country "into pieces" and claimed that if his critics came to power "it will be massacre".
"What happened in Ukraine will be just a walk in the park" in comparison, he said, in an apparent reference to a Kiev uprising and the outbreak of a separatist insurgency in Ukraine in 2014.
- UN calls for torture probe -
Lukashenko has proposed plans for a referendum on constitutional reforms, in what appears to be an attempt at compromise.
His election rival Svetlana Tikhanovskaya rejected the proposal on Tuesday, accusing Lukashenko of playing for time.
"Citizens' demands come first, then reforms that are only possible after honest elections," she wrote on her Telegram channel.
Tikhanovskaya, a 37-year-old political novice who ran in the election after her husband was jailed and barred from the vote, insists she won the vote. She left the country and was granted refuge in Lithuania.
Russian Foreign Minister Sergei Lavrov on Tuesday voiced support for Lukashenko's proposal of constitutional reforms and denounced sanctions against Belarus as "unacceptable".
Lavrov said Western countries were "delivering verdicts" on events in Belarus, which Moscow considered "to be unacceptable in the modern world."
During the first days of demonstrations, Lukashenko's security forces detained thousands of protesters, many of whom accused police of beatings and torture.
On Tuesday, the UN's special rapporteur on torture said Belarus must "stop torturing protesters" and bring to justice any police officers who had beaten them with impunity.
Nils Melzer and 14 other UN human rights experts said they had received reports of 450 documented cases of torture and ill-treatment of people deprived of their liberty in the mass protests and arrests.
"We are extremely alarmed at the hundreds of allegations of torture and other ill-treatment in police custody," they said.