Several hundred people have also been arrested in connection with the protests, according to the country's police authority.
The pro-democratic demonstrations against police brutality and corruption have been held throughout the country and mark the 35th anniversary of the historic protests in 1990 with demands for free elections.
The demonstrators accuse the authorities of paying armed vandals to discredit their movement, while the government has compared the demonstrations to a "coup attempt".
Monday's violent clashes between police and demonstrators are one in a series of several violent protests in recent months.
According to KNCHR, criminal gangs are also said to have been present at today's demonstrations in Nairobi and fought side by side with the police – information that the police themselves deny.
