A day earlier, tensions flared at the border as hundreds of Belarus migrants sought to illegally push their way into Poland, escalating a crisis that has been simmering for months.

Lukashenko, who has been in power for 26 years, has shrugged off the scale of protests, saying they are sponsored by the West.

The crowd, waving white flags with a red stripe, marched to the beat of drums towards detention centres where political prisoners were believed to be held, according to pictures and videos posted on social media.