Nobel prize-winning author Svetlana Alexievich accused the authorities in Belarus of terrorising their own people today as another opposition politician was detained by masked men in plain clothes.

Maxim Znak was the latest figure to be seized in asystematic campaign by the government of President Alexander Lukashenko to round up leaders of a month-long mass protest movement.

"What is happening is terror against the people," said Ms Alexievich, who summoned supporters to her home. "We have to unite and not give up our intentions. There is a danger we will lose the country," she said.

In a show of solidarity with Ms Alexievich, who won the 2015 Nobel Prize for Literature, diplomats from at least seven European countries joined her in her flat. Lithuania said the envoys' aim was partly to protect the author from abuse.

Mr Znak was detained two days after another opposition leader, Maria Kolesnikova, was snatched in the street by masked men. Both are prominent leaders of protests demanding the resignation of Mr Lukashenko following a 9 August presidential election that the opposition says was rigged. Mr Lukashenko denies vote-rigging.

Ms Kolesnikova's lawyer, Lyudmila Kazak, said she was being detained over accusations of an illegal attempt to seize power.

The lawyer met Ms Kolesnikova today for the first time since her disappearance, saying she was put in a cell with six other people at a pretrial detention centre. Ms Kazak will request a forensic medical examination as Ms Kolesnikova had bruises on her body, she said, according to a statement by Ms Kolesnikova's team.

Mr Znak's detention leaves Ms Alexievich as the last member of the opposition's Coordination Council still active inside Belarus.

The rest have fled, been forced abroad or detained in a crackdown by Mr Lukashenko's security forces as he seeks to maintain his 26-year-old grip on power.

The interior ministry said 121 more protesters had been arrested yesterday. New protests broke out in Minsk on Wednesday evening and several people were arrested by masked security forces, local media footage showed.

Mr Lukashenko accuses Western countries of meddling by supporting the opposition. 

Linas Linkevicius, Lithuania's foreign minister, told Reuters diplomats were at Alexievich's apartment to monitor the situation, and "because it is harder to resort to brutal methods when diplomatic staff is around".

"They are visitors to citizen Alexievich, at her invitation," he said. "She is a citizen, she has a flat, and there are guests in the flat."

A Lithuanian diplomat at the flat said envoys from Austria, the Czech Republic, Germany, Poland, Slovakia and Sweden were there.

Russian news agencies quoted Mr Lukashenko as saying there was nothing to discuss with the opposition. He raised the possibility of constitutional reform and a new presidential election - suggestions he has made in the past - but said it was too early to say when they might happen.

The 66-year-old leader retains the backing of Russian President Vladimir Putin. The West has so far been cautious about the prospect of taking strong action that might provoke Russian intervention, but the European Union is drawing up a list of individuals to target with sanctions.

In the latest sign of Moscow's support for Mr Lukashenko, two banking sources told Reuters that Russia's prime minister and finance minister had told the country's biggest state lenders to ensure liquidity continues to flow to banks in Belarus.

For Russia, Belarus is strategically important as a buffer state against NATO and a transit country for its exports of oil and gas. Russian news agency RIA said Mr Lukashenko would visit Moscow for talks on Monday.

The detention of Mr Znak today was part of a criminal case against the opposition's Coordination Council "for inciting actions aimed at harming the national security of the Republic of Belarus," his lawyer Dmitry Laevsky said.

Fellow opposition leader Ms Kolesnikova was seized in similar circumstances on Monday. On Tuesday she thwarted an attempt to deport her by tearing up her passport to avoid being forced to cross the border into Ukraine, two of her allies said.