Kenyan demonstrators prepared to resume protests Thursday, a day after President William Ruto made a dramatic U-turn and withdrew contentious tax hikes following deadly rallies earlier in the week.

The demonstrations were sparked last week by the 2024 finance bill and took Ruto's government by surprise as the initially peaceful rallies gathered momentum across the country.

But dramatic scenes Tuesday outside parliament, which saw the partly ablaze complex breached and ransacked, left the nation reeling as a state-backed rights group counted 22 dead nationwide in the aftermath and vowed an investigation.

Addressing a shocked nation on Wednesday afternoon, Ruto said he would not sign the bill, and "it shall subsequently be withdrawn".

"The people have spoken," he said, adding that he would seek "engagement with the young people of our nation".

It was a marked shift from his tough-talking late-night address Tuesday when he likened some of the demonstrators to "criminals".

Nelly, 25, told AFP that she intended to join the march on Thursday, criticising Ruto's approach as a case of too little, too late.

"He could have done this earlier without people having to die," she said.

"So let it be known that we are marching tomorrow for a better future Kenya."

The death toll on Wednesday stood at 22, with 19 in the capital alone, according to Roseline Odede, chairwoman of the state-funded Kenya National Commission on Human Rights.

"This is the largest number of deaths (in) a single day protest," Odede said, adding that 300 people were injured across the country.

Simon Kigondu, president of the Kenya Medical Association, said he had never before seen "such a level of violence against unarmed people".

An official at Kenyatta National Hospital in Nairobi said Wednesday that medics were treating "160 people... some of them with bullet wounds".

Outside parliament -- where the protesters converged on Tuesday -- an AFP journalist saw dried blood on pavements, with the smell of tear gas still lingering in the air on Wednesday morning.

Rights watchdogs have also accused the authorities of abducting protesters.

The Kenyan leader had already rolled back some tax measures last week, prompting the treasury to warn of a gaping budget shortfall of 200 billion shillings ($1.6 billion).

Ruto said Wednesday that withdrawing the bill would mean a significant hole in funding for development programmes to help farmers and schoolteachers, among others.

The cash-strapped government had said previously that the increases were necessary to service Kenya's massive debt of some 10 trillion shillings ($78 billion), equal to roughly 70 percent of GDP.

The unrest has alarmed the international community, with Washington on Wednesday calling on Kenya to respect the right to peaceful protest and the UN urging "accountability" for the bloodshed.

Ruto's administration is under pressure from the IMF, which has urged the country to implement fiscal reforms in order to access crucial funding.