Pro-democracy protesters in Hong Kong clashed with police for the third day running on Sunday as they gear up for what are expected to be mass demonstrations to mark the 70th anniversary of communist rule in China on October 1.

The brutal scenes — in which police at one point fired a warning shot with live ammunition, according to a witness — came as supporters of Hong Kong’s pro-democracy movement rallied in other cities around the world over the weekend, including Sydney, Berlin and London.

Protesters in the Asian financial hub on Sunday threw Molotov cocktails and vandalised government buildings and underground railway stations. Some also burned banners put up to mark the forthcoming national day of the People’s Republic of China. Police responded with tear gas, pepper spray and water cannons.