Zambia voting for president amid unprecedented violence

FILE -- In this Jan. 2015 file photo Hakainde Hichilema, of the Zambia opposition United Party for National Development addresses an election rally in Lusaka, Zambia. This southern African country votes in a presidential election Thursday Aug. 11, 2016, amid widespread concerns about possible political violence as President Edgar Lungu faces off against businessman contender Hakainde Hichilema. (AP Photo/Tsvangirayi Mukwazhi, File) (The Associated Press)

FILE - In this Sept. 2015, file photo Zambia's President Edgar Lungu speaks during the 70th session of the United Nations General Assembly at U.N. headquarters. Zambia votes in a presidential election Thursday Aug. 11, 2016, amid widespread concerns about possible political violence as President Lungu faces off against businessman contender Hakainde Hichilema. (AP Photo/Frank Franklin II, FILE) (The Associated Press)

Supporters of the United Party for National Development opposition party attend an election rally on the eve of the country's presidential elections in Lusaka, Zambia, Wednesday, Aug. 10, 2016. This southern African country votes Thursday amid concerns about political violence after years of peaceful power transitions that the U.S. last year praised as a "model for Africa." (AP Photo/Moses Mwape) (The Associated Press)

Zambia, often praised for its democracy and healthy economy, now faces a presidential election with high tensions on both fronts.

This southern African country votes Thursday amid concerns about political violence and local media restrictions, as well as economic problems caused by the drop in the price of its main export, copper.

Candidates include President Edgar Lungu, who has been in office for just a year and a half, and businessman Hakainde Hichilema of the opposition United Party for National Development. Lungu took office in January 2015 after the death of President Michael Sata.

For the first time, a candidate must win more than 50 percent of the vote or face a runoff election.

The head of the electoral commission has called the violence ahead of this year's vote unprecedented.