At least ten people were shot dead in Kenya's capital on Tuesday, a paramedic said, as protests against tax legislation turned into violent clashes with police and a section of the parliament was set up in flames.

AFP journalists saw three people lying motionless on the ground near the compound, where police fired live rounds and left "many wounded", according to Amnesty International Kenya.

Police fired at crowds massing outside the parliament building, where lawmakers had been debating a contentious bill featuring tax hike proposals.

Shortly before, Irungu Houghton, the executive director of Amnesty International Kenya, told AFP that "human rights observers are now reporting the increasing use of live bullets by the National Police Service in the capital of Nairobi".

"Safe passage for medical officers to treat the many wounded is now urgent," he said.

The mainly Gen-Z-led rallies began last week and had been mostly peaceful, with President William Ruto saying over the weekend he was ready to talk to the protesters.

But tensions sharply escalated on Tuesday afternoon, as crowds began to throw stones at police and push back against barricades, making their way towards the parliament complex, which was sealed off by police in full riot gear.

Anger over a cost-of-living crisis spiralled into nationwide rallies last week, with demonstrators calling for the finance bill to be scrapped.