Police in Belarus detained 313 people during Sunday's latest demonstrations against President Alexander Lukashenko to step down, the Interior Ministry said.
Thousands attended protests in the capital, Minsk, and other cities, which have rocked Belarus since Lukashenko's disputed re-election in August.
Opposition supporters and the European Union have refused to recognise the result, saying the vote was rigged.
On Sunday, police once again deployed tear gas and stun grenades to break up some of the crowds, according to the Viasna human rights centre.
Viasna says that as many as 416 people were detained on the 16th consecutive Sunday protest.
Large crowds had gathered on the streets despite snowy weather to block the roads in some areas, some carrying banners saying "``Neighbour for neighbour against dictatorship".
Ahead of the rally, water cannons, armoured vehicles, and police vans were seen in the centre of Minsk, while several subway stations were closed.
On Saturday, opposition figure Svetlana Tsikhanouskaya, who left the country soon after the election under pressure from the authorities and is currently in exile in Lithuania, extended her support to the protesters.
"I will support everyone who takes part in the Neighbors' March this Sunday,'' Tsikhanouskaya said in a video statement.
"We have come a long, hard way together already ... we are a proud, brave, peaceful people that have learned the price of freedom and will never agree to live without it."
Belarus' opposition has been demanding Lukashenko's resignation, an end to police violence against peaceful demonstrators and new elections in the country.
On Friday, President Lukashenko said he would not remain in the post he has held for more than 26 years if Belarus adopts a new constitution, but did not give further details.
The EU said last week that they had planned new sanctions against Belarusian business, in response to the "brutality of authorities".