Fifty-three children have been rushed to hospital in Nairobi after tear gas was thrown into their classroom by police during protests.
Dr Aron Shikuku of Eagle Nursing Home Hospital told the BBC they have now stabilized the unconscious children.
There were protests across the country called by the opposition against the rising cost of living, but they turned deadly.
Six people were killed, authorities said.
Human rights bodies, however, put the death toll at 12, with many others injured.
Two people died after protesters set fire to a police station, while another died in an attack on a police van along the Nairobi highway on the outskirts of the city, according to reports .
Protests had been banned but people still took to the streets, such is the anger of some Kenyans over rising living costs and a new finance bill – which includes tax hikes .
Controversial hikes include doubling fuel taxes and imposing a 1.5% tax on all employees to fund new homes.
The government says the hikes are essential to repay debts and create job opportunities for young people, but the law was suspended by a court on constitutional grounds.
Opposition leader Raila Odinga, who was beaten by Mr Ruto in last year’s election, has pressured the government to roll back tax hikes, calling for civil disobedience the month last and calling those who want to implement the finance bill “traitors”.
An opposition rally was scheduled for Wednesday, but Mr Odinga called it off, saying he wanted to avoid further violence.
Police chief Japhet Koome said on Tuesday that “all legal means” would be used to break up the protests, AFP news agency reported.
These latest protests come just days after several people were killed in anti-government protests last Friday, in which human rights groups accused Kenyan police of excessive use of the strength.
Kenyans are divided over the protests, with some backing them, saying the high cost of living is unsustainable: “Kenyans are defending themselves personally, arguing against the taxes imposed. The salary you get versus what you spend, there’s nothing significant you can do for yourself as a human being,” William Musembi told Reuters news agency.
While others complained of looting: ‘A group of about 400 to 500 people were gathering along the highway and they all came at once and broke down the doors which were already locked,’ said supermarket manager James Kagimi Wanjema told Reuters.
“They were able to access the boxes, they looted money and goods. It’s a bit chaotic, very chaotic,” he said.