Riot police fired warning shots into the air, used stun grenades and made arrests to deter tens of thousands of Belarusians who marched through Minsk on Sunday to demand Alexander Lukashenko leave power.

This week Lukashenko partially closed the border to the west, replaced his interior minister and said that any protester who lays a hand on officers policing the protests should “at least leave without hands”.

Belarusian riot police used force to disperse marchers who had reached Kuropaty, a memorial site on the outskirts of Minsk to victims of execution by Soviet secret police. “People got to a field near Kuropaty, (police) buses pulled up and chased after people at top speed, then they started throwing grenades. What’s more, they were throwing them into the thick of the crowd,” the witness said by phone on condition of anonymity.

“A lot of people have been detained. It all happened in an open field, so there was nowhere to run,” the witness who requested anonymity said.