Thousands of people marched on Sunday in Brussels urging the Belgian government to respect its commitments on countering climate change as a United Nations conference on keeping global warming in check begins in Poland.

The demonstration in the centre of the Belgian capital took place two days after a few hundred people, inspired by France's "yellow vest" anti-tax movement, protested near the Belgian parliament against high fuel prices.

Belgian police said some 65,000 people participated to Sunday's "Claim The Climate" demonstration, many of them on their bikes.

Demonstrators called for "ambitious" climate policies to limit global warming to 1.5 degrees Celsius in line with goals set by the Paris Agreement in 2015.

The peaceful Sunday march contrasted with the much smaller yellow-vest protests that degenerated into violence on Friday. While the yellow vests called for lower fuel prices, demonstrators on Sunday wanted a reduction of gas emissions.

Organisers of the climate march urged more renewable energy, more cycling paths and cleaner air, through "a socially just transition".

The Brussels demonstration coincided with the beginning of a two-week UN summit on climate change in the Polish city of Katowice.