ACCRA (Reuters) - Ghana riot police fired tear gas on Sunday to disperse more than 200 opposition supporters protesting in front of the election commission ahead of poll results.

Youths carrying sticks and shouting "We want justice" had assembled there after a spokesman for the opposition National Patriotic Party said electoral workers had tampered with the results of a presidential election.

The election commission has not yet announced a winner from the presidential race, but local media have projected incumbent leader John Dramani Mahama narrowly beat his NPP rival Nana Akufo-Addo with just over 50 percent.

(Reporting by Kwasi Kpodo; Writing by Richard Valdmanis)