Tens of thousands of belarusians marched against president alexander lukashenko on sunday, defying a heavy presence of security forces and the threat of mass arrests as protests against the strongman leaders re-election entered a seventh week.

Armoured police trucks and a water cannon were deployed in the centre of minsk alongside hundreds of riot police and soldiers in black balaclavas and helmets, who chased protesters, beat them to the ground and dragged them to waiting trucks, according to videos posted on social media.

Mr lukashenko has ruled belarus for 26 years and claimed to have won his sixth presidential election on aug 9 with 80 per cent of a vote that many countries have said was rigged.

The protests that have since engulfed belarus are the biggest in its post-soviet history, but mr lukashenko has managed to cling to power thanks to a brutal police crackdown, the arrest or expulsion of almost all his opponents from the country and the support of his longtime ally russian president vladimir putin.

The protests, which took place in cities across the country, come ahead of a meeting of eu foreign ministers on monday to discuss the blocs response to the crisis. brussels has vowed to impose sanctions on officials involved in the electoral fraud and the violent repression of protesters but has failed to reach a final agreement on the details of the response.

Viasna, a belarusian human rights organisation, said more than 80 people had been arrested early on sunday evening, a number that was likely to rise. sundays rallies came after police detained more than 400 protesters attending a womens protest on saturday.

People arrested in previous rallies over the past six weeks have claimed they were abused and physically assaulted by police while in custody.

Mr lukashenko, a former soviet collective farm boss who has maintained an iron-like grip on power since 1994 by repressing independent media, imprisoning his political opponents and ensuring state-run enterprises dominate the economy, has steadfastly refused to bow to the popular unrest.

His confidence was bolstered last week by a visit to moscow where mr putin promised $1.5bn in financial aid and joint russian-belarusian military exercises.

Mr putin has formed a russian police division that he says is ready to cross the border and deploy on belarus streets if the protests escalate, signifying the kremlins resolve to use force toprevent a revolutionin its closest client state.

Alongside moscows continued support for his regime, the loyalty of belarus military, police and security forces is seen as the critical pillar of support keeping mr lukashenko in office.

Ahead of sundays marches, pro-opposition social media channels shared alleged personal data of 1,000 police officers in response to the heavy-handed crackdown on protesters, and warned that it would continue to publish more data on security forces if arrests continued.

Protesters have in recent weeks sought to pull the balaclavas off the faces of police officers involved in detentions in an attempt to identify them. belarus interior ministry appeared to confirm the authenticity of the leaked data by saying it would track down those responsible and prosecute them.