HARARE, Zimbabwe—The Zimbabwe prime minister's party says its minister of energy was detained for questioning by police on allegations he insulted President Robert Mugabe by wishing him dead.

The party says Elton Mangoma, who is in charge of power and gasoline supplies in the troubled economy, was released later Wednesday. He allegedly said at a political meeting in May: "Mugabe die. Mugabe go."

It is an offense under sweeping security laws to undermine the authority of the 88-year-old longtime ruler Mugabe.

Insult offenses, with a penalty of a fine or imprisonment, are common. A Zimbabwean salesman spent four months in jail earlier this year after being found with cartoons of a naked Mugabe on his mobile phone.

Mangoma was cleared last year on corruption charges he says were a political ploy.