LUSAKA, Zambia (AP) — Police in Zambia say two people have been shot dead after a huge and “unruly” crowd accompanied a top opposition leader who had been summoned to police headquarters.

The police statement says people had been advised to "stay away” as Hakainde Hichilema was arriving Wednesday in response to a summons in the capital, Lusaka. But it says officers used tear gas to disperse the crowd and two people were killed “in unknown circumstances.”

The southern African nation faces a presidential election in the middle of next year. After an unusually tense election in 2016, Hichilema was detained and charged with treason in 2017 before he was released amid an outcry. He had been accused of blocking President Edgar Lungu’s motorcade with his own convoy.

Hichilema now says police are “waging war against citizens” as the campaigning for next year begins, and the chair of his United Party for National Development, Mutale Nalumango, blames the new violence on the ruling Patriotic Front.

Police say they are waiting for the results of forensic examinations to determine what kind of firearm was used.