KYIV, UKRAINE -- A human rights group in Belarus says over 300 people have been detained during Sunday protests against the country's authoritarian president, who won his sixth term in office in a vote widely seen as rigged.

The protests took place in Minsk, the capital, and other cities and attracted thousands of people. In Minsk, large crowds gathered in different parts of the city despite the snowy weather for what has been dubbed as the Neighbors' March, blocking the roads in some areas.

"Neighbour for neighbour against dictatorship," one protest banner read.

"Go away, rat!" the crowds chanted, referring to President Alexander Lukashenko, who has run the country for 26 years, relentlessly cracking down on dissent.

Nearly 250 demonstrators were detained in Minsk alone, police said.

Mass protests have gripped Belarus, a former Soviet republic in eastern Europe, since official results from the Aug. 9 presidential election gave Lukashenko a landslide victory over his widely popular opponent, Sviatlana Tsikhanouskaya. She and her supporters refused to recognize the result, saying the vote was riddled with fraud.

Authorities have cracked down hard on the largely peaceful demonstrations, the biggest of which attracted up to 200,000 people. Police used stun grenades, tear gas and truncheons to disperse the rallies.

On Sunday, police once again deployed tear gas and stun grenades to break up some of the crowds in Minsk, and some were chased into residential courtyards and beaten up with truncheons, the Viasna human rights centre said. More than 300 people have been detained all across the country, according to the group.

Ahead of the rally, water cannons, armoured vehicles and police vans were seen in the centre of Minsk. Several subway stations were closed and internet access was restricted.

On Saturday, 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're a proud, brave, peaceful people that have learned the price of freedom and will never agree to live without it."