A Kenyan activist says police have tear-gassed a peaceful demonstration in support of government action against corruption.

Boniface Mwangi said about 200 demonstrators held a peaceful march Tuesday to the Supreme Court and parliament where they delivered a petition asking those institutions to do more to tackle corruption in the East African country.

Police blocked the protesters' attempts to proceed to State House, the official residence of President Uhuru Kenyatta.

Mwangi, who organized the protests, said that he is among 26 people arrested. Mwangi said he is surprised by the police action because the demonstration was peaceful and in support of government action against those implicated in corruption.

Kenya was ranked 145 out 174 countries in Transparency International's 2014 index of perception of graft.