Police fired tear gas to clear pockets of anti-government demonstrators from the centre of Kenya's capital Nairobi on Thursday, as their protest movement sought to capitalise on earlier concessions and compel President William Ruto to resign.

The "Nane Nane" march, meaning "eight eight" in reference to the date, follows weeks of similar pro-reform protests that saw Ruto scrap planned tax hikes and overhaul his cabinet.

The youth-led nationwide protests began peacefully in June before turning violent, and more than 50 people have been killed.

Shops were shut and streets left deserted after riot police set up roadblocks and threw tear gas canisters to disperse handfuls of protesters across Nairobi's financial district. Police fired tear gas at one group of a dozen protesters chanting "Ruto must go", a Reuters journalist reported.