Thousands of demonstrators flooded a downtown avenue in Buenos Aires to protest the G20 summit taking place in the Argentinian capital.

The protesters waved flags and held up banners with slogans including "Go away G-20" and "Go away Trump".

Activists from France, Germany, Italy and several Latin American nations are taking part alongside Argentinians in a demonstration organised by left-leaning groups and labour unions.

The demonstration is 10 kilometres from the summit venue.

About 22,000 police officers and other security forces are guarding the leaders during the two-day summit.