NAIROBI, Kenya (AP) — Polling stations across Tanzania opened Wednesday for an election marked by concerns from human rights organizations and the detention of opposition members.

President Samia Suluhu Hassan is seeking a second term. He belongs to the ruling Chama Cha Mapinduzi party, which has governed the country since it gained independence in 1961.

Queues formed at three polling stations visited by Associated Press journalists. Voting officially began at 7:00 a.m. local time and is scheduled to close at 4:00 p.m., after which vote tallying will begin.

Preliminary results are expected within 24 hours, but the electoral commission has up to seven days to announce the final outcome.

The leader of the main opposition CHADEMA party, Tundu Lissu, is in prison and faces treason charges after calling for electoral reforms, while the second largest opposition party's candidate was barred from running.