Youths injured an NTV cameraman and stoned vehicles after a rally addressed by Nasa leader Raila Odinga in Migori town ended, with police using tear gas to disperse them.
At least 10 vehicles were pelted with stones, including one belonging to the Nation Media Group, an Isuzu D-Max double-cab, which had its windscreen smashed.
A campaign caravan belonging to incumbent Governor Okoth Obado was also damaged.
The youths barricaded the road at Posta roundabout and attacked motorists on the highway.
They chanted slogans in praise of the various candidates seeking the region’s gubernatorial seat.
Mr Benard Ojwang, the cameraman, was hit by a stone and complained of pain in his lower abdomen.