Kenyans are voting amid tight security in a re-run of the presidential election, which is being boycotted by the main opposition.

A teenager has died in clashes in the opposition stronghold of Kisumu in the west, where some people have blocked access to polling stations.

President Uhuru Kenyatta was declared the winner in an August vote, but it is being held again over "irregularities".

Turnout appears high in ruling party strongholds but lower elsewhere.

Mr Kenyatta is seeking a second term. Opposition leader Raila Odinga has pulled out of the contest.