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NAIROBI, Jan 17 (Reuters) - Kenyan riot police fired teargas at hundreds of protesters blocking a road near Nairobi's Mathare slum as a second day of demonstrations against President Mwai Kibaki's disputed election began on Thursday, witnesses said.

Gunshots were also heard during the morning from a slum area of the western opposition stronghold town of Kisumu, which saw the worst violence on Wednesday, the first of three days of nationwide demonstrations called by the opposition.

The Orange Democratic Movement (ODM) hopes three days of protests will put pressure on Kibaki, which it accuses of stealing the Dec. 27 presidential election.

But police have banned the rallies, and took tough action against protesters on Wednesday, killing at least three during a day of fighting in Kisumu. (Reporting by Antony Njuguna in Nairobi, Guled Mohamed in Kisumu; Writing by Andrew Cawthorne; Editing by Dominic Evans)

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