Two men are on trial in Zambia on charges of practicing witchcraft and possessing charms intended to harm the country’s president.

Supporters of Zambian opposition candidate Hakainde Hichilema have begun celebrating as early election results show him leading in the tightly-fought, tense presidential race.

Zambia’s standing as one of Africa’s most stable democracies is being tested this week in the vote in which President Edgar Lungu is seeking re-election.

Zambia’s president Monday opened a sprawling new Chinese-funded and built terminal at the main airport in the capital, Lusaka, days before crucial polls, warning that election-related violence could shatter the stability of one of Africa’ most peaceful nations.

Zambia is on “the brink of a human rights crisis,” Amnesty International said Monday, alleging that President Edgar Lungu faces is using repressive tactics to win another term in elections set for Aug. 12.