Political protests in Kiev turned into a showdown with police after a morning that saw opposition supporters attempting to overturn cars.

It wasn't long before more demonstrators and riot police were in a shoving match. Several people were injured in the clashes --- some of them between police and demonstrators and others between rival political groups.

Opposition supporters of different political stripes have vowed to work together defeat President Viktor Yanukovich. Many here blame him for not securing better trade deals with Europe.

Opposition leader and champion boxer Vitaly Klitschko.

SOUNDBITE: Opposition leader and champion boxer Vitaly Klitscho saying (Ukrainian):

"I'm certain that we can beat this dictatorship which is imposed on us today. We are united by the fight against today's dictatorship, we are united by the desire to live in a modern European country and we will reach this. We will fight for this and we will win."

Supporters of