KAMPALA, Uganda (AP) — Long lines of Ugandans have voted in a presidential election tainted by widespread violence that some fear could escalate as security forces try to stop supporters of leading opposition challenger Bobi Wine from monitoring polling stations. Longtime leader Yoweri Museveni seeks a sixth term against a strong challenge from the young singer and lawmaker who has captured the imagination of many across Africa who say they are tired of leaders who never leave. The government has shut down internet access, and the military is on the streets of the capital. The country has never witnessed a peaceful handover of power since independence.