It was one of of Karzai's first outdoor public appearances since an assassination attempt last year. Karzai, who appeared at a football stadium, has limited his outdoor appearances since the attempt to kill him at a military parade last year.
Karzai remains a frontrunner but faces a serious challenge from his main rival, Abdullah Abdullah, a former foreign minister in his cabinet.
There are fears violence could threaten the country's second presidential election.
Photograph: Reuters/Omar Sobhani