NAIROBI (Reuters) - Police in Kenya fired tear gas on Tuesday to disperse hundreds of protesters aiming to keep pressure on President William Ruto after he made a series of concessions to demonstrators' demands.

Leading activists behind weeks of protests, initially sparked by proposed tax hikes, called for a "total shutdown" of the country on Tuesday.

The protests have created the biggest crisis of Ruto's two years in power and have continued - albeit with a smaller turnout - even after the president withdrew $2.7 billion in tax hikes and fired nearly his entire cabinet.

Many demonstrators are demanding that Ruto step down, blaming him for misgovernance, corruption and the deaths of dozens of protesters during earlier anti-government rallies.

On Tuesday, police fired tear gas in Kitengela, a town on the southern outskirts of the capital Nairobi, where around 200 protesters burned tyres and chanted "Ruto must go" and "Stop killing us", Reuters reporters said.

Riot police in Nairobi's city centre also fired tear gas as a few dozen protesters chanted for Ruto to step down. Demonstrators in the coastal city of Mombasa marched waving palm fronds, footage from Kenyan media showed.

Ruto's office had announced "multi-sectoral" talks for this week to address grievances raised by the protesters, but there was no sign they had begun. Most of the leading activists behind the protests have rejected the invitation, instead calling for immediate action on issues like corruption.

Ruto's spokesperson did not immediately respond to a request for comment.

With Kenya spending over 30% of its revenues just paying the interest bills on its debt, Ruto has been caught between the demands of lenders to cut deficits and a hard-pressed population reeling from rising living costs.

The protests began peacefully but later turned violent. Some demonstrators briefly stormed parliament on June 25, and the police opened fire. More than 40 people have been killed in the protests, rights groups say.

Ruto on Monday accused the Ford Foundation, an American philanthropic organisation, of sponsoring those who had caused "violence and mayhem" in Kenya, without providing evidence.

The Ford Foundation rejected the allegation, saying it did not fund or sponsor the protests and has a strictly non-partisan policy for its grant-making.

(Additional reporting by Hereward Holland and Humphrey Malalo; Editing by Aaron Ross and Ros Russell)

By Thomas Mukoya and Monicah Mwangi