Police in Belarus broke up crowds of protesters with stun grenades, and water cannon as long-time leader Alexander Lukashenko looked set to declare an overwhelming victory in a presidential poll his opponents say was rigged.

Thousands of protesters took to the streets of the capital Minsk after a state exit poll showed Lukashenko winning just under 80 percent in Sunday’s election, with the main challenger Svetlana Tikhanovskaya coming second with about seven percent.

Tikhanovskaya, a 37-year-old stay-at-home mother and political novice, galvanized the opposition during the election campaign, attracting tens of thousands of supporters to the ex-Soviet country’s biggest demonstrations in years.

In the capital, Minsk protesters gathered near a central monument late Sunday, where they faced off with hundreds of riot police with shields.